This is my report from the Netfilter Workshop 2022. The event was held on 2022-10-20/2022-10-21 in Seville, and the venue was the offices of Zevenet. We started on Thursday with Pablo Neira (head of the project) giving a short welcome / opening speech. The previous iteration of this event was in virtual fashion in 2020, two years ago. In the year 2021 we were unable to meet either in person or online. This year, the number of participants was just eight people, and this allowed the setup to be a bit more informal. We had kind of an un-conference style meeting, in which whoever had something prepared just went ahead and opened a topic for debate. In the opening speech, Pablo did a quick recap on the legal problems the Netfilter project had a few years ago, a topic that was settled for good some months ago, in January 2022. There were no news in this front, which was definitely a good thing. Moving into the technical topics, the workshop proper, Pablo started to comment on the recent developments to instrument a way to perform inner matching for tunnel protocols. The current implementation supports VXLAN, IPIP, GRE and GENEVE. Using nftables you can match packet headers that are encapsulated inside these protocols. He mentioned the design and the goals, that was to have a kernel space setup that allows adding more protocols by just patching userspace. In that sense, more tunnel protocols will be supported soon, such as IP6IP, UDP, and ESP. Pablo requested our opinion on whether if nftables should generate the matching dependencies. For example, if a given tunnel is UDP-based, a dependency match should be there otherwise the rule won t work as expected. The agreement was to assist the user in the setup when possible and if not, print clear error messages. By the way, this inner thing is pure stateless packet filtering. Doing inner-conntracking is an open topic that will be worked on in the future. Pablo continued with the next topic: nftables automatic ruleset optimizations. The times of linear ruleset evaluation are over, but some people have a hard time understanding / creating rulesets that leverage maps, sets, and concatenations. This is where the ruleset optimizations kick in: it can transform a given ruleset to be more optimal by using such advanced data structures. This is purely about optimizing the ruleset, not about validating the usefulness of it, which could be another interesting project. There were a couple of problems mentioned, however. The ruleset optimizer can be slow, O(n!) in worst case. And the user needs to use nested syntax. More improvements to come in the future. Next was Stefano Brivio s turn (Red Hat engineer). He had been involved lately in a couple of migrations to nftables, in particular libvirt and KubeVirt. We were pointed to https://libvirt.org/firewall.html, and Stefano walked us through the 3 or 4 different virtual networks that libvirt can create. He evaluated some options to generate efficient rulesets in nftables to instrument such networks, and commented on a couple of ideas: having a null matcher in nftables set expression. Or perhaps having kind of subsets, something similar to a view in a SQL database. The room spent quite a bit of time debating how the nft_lookup API could be extended to support such new search operations. We also discussed if having intermediate facilities such as firewalld could provide the abstraction levels that could make developers more comfortable. Using firewalld also may have the advantage that coordination between different system components writing ruleset to nftables is handled by firewalld itself and developers are freed of the responsibility of doing it right. Next was Fernando F. Mancera (Red Hat engineer). He wanted to improve error reporting when deleting table/chain/rules with nftables. In general, there are some inconsistencies on how tables can be deleted (or flushed). And there seems to be no correct way to make a single table go away with all its content in a single command. The room agreed in that the commands destroy table and delete table should be defined consistently, with the following meanings:

• destroy: nuke the table, don t fail if it doesn t exist
• delete: delete the table, but the command will fail if it doesn t exist

This topic diverted into another: how to reload/replace a ruleset but keep stateful information (such as counters). Next was Phil Sutter (Netfilter coreteam member and Red Hat engineer). He was interested in discussing options to make iptables-nft backward compatible. The use case he brought was simple: What happens if a container running iptables 1.8.7 creates a ruleset with features not supported by 1.8.6. A later container running 1.8.6 may fail to operate. Phil s first approach was to attach additional metadata into rules to assist older iptables-nft in decoding and printing the ruleset. But in general, there are no obvious or easy solutions to this problem. Some people are mixing different tooling version, and there is no way all cases can be predicted/covered. iptables-nft already refuses to work in some of the most basic failure scenarios. An other way to approach the issue could be to introduce some kind of support to print raw expressions in iptables-nft, like -m nft xyz. Which feels ugly, but may work. We also explored playing with the semantics of release version numbers. And another idea: store strings in the nft rule userdata area with the equivalent matching information for older iptables-nft. In fact, what Phil may have been looking for is not backwards but forward compatibility. Phil was undecided which path to follow, but perhaps the most common-sense approach is to fall back to a major release version bump (2.x.y) and declaring compatibility breakage with older iptables 1.x.y. That was pretty much it for the first day. We had dinner together and went to sleep for the next day. The second day was opened by Florian Westphal (Netfilter coreteam member and Red Hat engineer). Florian has been trying to improve nftables performance in kernels with RETPOLINE mitigations enabled. He commented that several workarounds have been collected over the years to avoid the performance penalty of such mitigations. The basic strategy is to avoid function indirect calls in the kernel. Florian also described how BPF programs work around this more effectively. And actually, Florian tried translating nf_hook_slow() to BPF. Some preliminary benchmarks results were showed, with about 2% performance improvement in MB/s and PPS. The flowtable infrastructure is specially benefited from this approach. The software flowtable infrastructure already offers a 5x performance improvement with regards the classic forwarding path, and the change being researched by Florian would be an addition on top of that. We then moved into discussing the meeting Florian had with Alexei in Zurich. My personal opinion was that Netfilter offers interesting user-facing interfaces and semantics that BPF does not. Whereas BPF may be more performant in certain scenarios. The idea of both things going hand in hand may feel natural for some people. Others also shared my view, but no particular agreement was reached in this topic. Florian will probably continue exploring options on that front. The next topic was opened by Fernando. He wanted to discuss Netfilter involvement in Google Summer of Code and Outreachy. Pablo had some personal stuff going on last year that prevented him from engaging in such projects. After all, GSoC is not fundamental or a priority for Netfilter. Also, Pablo mentioned the lack of support from others in the project for mentoring activities. There was no particular decision made here. Netfilter may be present again in such initiatives in the future, perhaps under the umbrella of other organizations. Again, Fernando proposed the next topic: nftables JSON support. Fernando shared his plan of going over all features and introduce programmatic tests from them. He also mentioned that the nftables wiki was incomplete and couldn t be used as a reference for missing tests. Phil suggested running the nftables python test-suite in JSON mode, which should complain about missing features. The py test suite should cover pretty much all statements and variations on how the nftables expression are invoked. Next, Phil commented on nftables xtables support. This is, supporting legacy xtables extensions in nftables. The most prominent problem was that some translations had some corner cases that resulted in a listed ruleset that couldn t be fed back into the kernel. Also, iptables-to-nftables translations can be sloppy, and the resulting rule won t work in some cases. In general, nft list ruleset nft -f may fail in rulesets created by iptables-nft and there is no trivial way to solve it. Phil also commented on potential iptables-tests.py speed-ups. Running the test suite may take very long time depending on the hardware. Phil will try to re-architect it, so it runs faster. Some alternatives had been explored, including collecting all rules into a single iptables-restore run, instead of hundreds of individual iptables calls. Next topic was about documentation on the nftables wiki. Phil is interested in having all nftables code-flows documented, and presented some improvements in that front. We are trying to organize all developer-oriented docs on a mediawiki portal, but the extension was not active yet. Since I worked at the Wikimedia Foundation, all the room stared at me, so at the end I kind of committed to exploring and enabling the mediawiki portal extension. Note to self: is this perhaps https://www.mediawiki.org/wiki/Portals ? Next presentation was by Pablo. He had a list of assorted topics for quick review and comment.

• We discussed nftables accept/drop semantics. People that gets two or more rulesets from different software are requesting additional semantics here. A typical case is fail2ban integration. One option is quick accept (no further evaluation if accepted) and the other is lazy drop (don t actually drop the packet, but delay decision until the whole ruleset has been evaluated). There was no clear way to move forward with this.
• A debate on nft userspace memory usage followed. Some people are running nftables on low end devices with very little memory (such as 128 MB). Pablo was exploring a potential solution: introducing struct constant_expr, which can reduce 12.5% mem usage.
• Next we talked about repository licensing (or better, relicensing to GPLv2+). Pablo went over a list of files in the nftables tree which had diverging licenses. All people in the room agreed on this relicensing effort. A mention to the libreadline situation was made.
• Another quick topic: a bogus EEXIST in nft_rbtree. Pablo & Stefano to work in a patch.
• Next one was conntrack early drop in flowtable. Pablo is studying use cases for some legitimate UDP unidirectional flows (like RTP traffic).
• Pablo and Stefano discussed pipapo not being atomic on updates. Stefano already looked into it, and one of the ideas was to introduce a new commit API for sets.
• The last of the quick topics was an idea to have a global table in nftables. Or some global items, like sets. Folk in the community keep asking for this. Some ideas were discussed, like perhaps adding a family agnostic family. But then there would be a challenge: nftables would need to generate byte code that works in any of the hooks. There was no immediate way of addressing this. The idea of having templated tables/sets circulated again as a way of reusing data across namespaces/families.

Following this, a new topic was introduced by Stefano. He wanted to talk about nft_set_pipapo, documentation, what to do next, etc. He did a nice explanation of how the pipapo algorithm works for element inserts, lookups, and deletion. The source code is pretty well documented, by the way. He showed performance measurements of different data types being stored in the structure. After some lengthly debate on how to introduce changes without breaking usage for users, he declared some action items: writing more docs, addressing problems with non-atomic set reloads and a potential rework of nft_rbtree. After that, the next topic was kubernetes & netfilter , also by Stefano. Actually, this topic was very similar to what we already discussed regarding libvirt. Developers want to reduce packet matching effort, but also often don t leverage nftables most performant features, like sets, maps or concatenations. Some Red Hat developers are already working on replacing everything with native nftables & firewalld integrations. But some rules generators are very bad. Kubernetes (kube-proxy) is a known case. Developers simply won t learn how to code better ruleset generators. There was a good question floating around: What are people missing on first encounter with nftables? The Netfilter project doesn t have a training or marketing department or something like that. We cannot force-educate developers on how to use nftables in the right way. Perhaps we need to create a set of dedicated guidelines, or best practices, in the wiki for app developers that rely on nftables. Jozsef Kadlecsik (Netfilter coreteam) supported this idea, and suggested going beyond: such documents should be written exclusively from the nftables point of view: stop approaching the docs as a comparison to the old iptables semantics. Related to that last topic, next was Laura Garc a (Zevenet engineer, and venue host). She shared the same information as she presented in the Kubernetes network SIG in August 2020. She walked us through nftlb and kube-nftlb, a proof-of-concept replacement for kube-proxy based on nftlb that can outperform it. For whatever reason, kube-nftlb wasn t adopted by the upstream kubernetes community. She also covered latest changes to nftlb and some missing features, such as integration with nftables egress. nftlb is being extended to be a full proxy service and a more robust overall solution for service abstractions. In a nutshell, nftlb uses a templated ruleset and only adds elements to sets, which is exactly the right usage of the nftables framework. Some other projects should follow its example. The performance numbers are impressive, and from the early days it was clear that it was outperforming classical LVS-DSR by 10x. I used this opportunity to bring a topic that I wanted to discuss. I ve seen some SRE coworkers talking about katran as a replacement for traditional LVS setups. This software is a XDP/BPF based solution for load balancing. I was puzzled about what this software had to offer versus, for example, nftlb or any other nftables-based solutions. I commented on the highlighs of katran, and we discussed the nftables equivalents. nftlb is a simple daemon which does everything using a JSON-enabled REST API. It is already packaged into Debian, ready to use, whereas katran feels more like a collection of steps that you need to run in a certain order to get it working. All the hashing, caching, HA without state sharing, and backend weight selection features of katran are already present in nftlb. To work on a pure L3/ToR datacenter network setting, katran uses IPIP encapsulation. They can t just mangle the MAC address as in traditional DSR because the backend server is on a different L3 domain. It turns out nftables has a nft_tunnel expression that can do this encapsulation for complete feature parity. It is only available in the kernel, but it can be made available easily on the userspace utility too. Also, we discussed some limitations of katran, for example, inability to handle IP fragmentation, IP options, and potentially others not documented anywhere. This seems to be common with XDP/BPF programs, because handling all possible network scenarios would over-complicate the BPF programs, and at that point you are probably better off by using the normal Linux network stack and nftables. In summary, we agreed that nftlb can pretty much offer the same as katran, in a more flexible way. Finally, after many interesting debates over two days, the workshop ended. We all agreed on the need for extending it to 3 days next time, since 2 days feel too intense and too short for all the topics worth discussing. That s all on my side! I really enjoyed this Netfilter workshop round.

Once a year folks interested in Netfilter technologies gather together to discuss past, ongoing and future works. The Netfilter Workshop is an opportunity to share and discuss new ideas, the state of the project, bring people together to work & hack and to put faces to people who otherwise are just email names. This is an event that has been happening since at least 2001, so we are talking about a genuine community thing here. It was decided there would be an online format, split in 3 short meetings, once per week on Fridays. I was unable to attend the first session on 2020-11-06 due to scheduling conflict, but I made it to the sessions on 2020-11-13 and 2020-11-20. I would say the sessions were joined by about 8 to 10 people, depending on the day. This post is a summary with some notes on what happened in this edition, with no special order. Pablo did the classical review of all the changes and updates that happened in all the Netfilter project software components since last workshop. I was unable to watch this presentation, so I have nothing special to comment. However, I ve been following the development of the project very closely, and there are several interesting things going on, some of them commented below. Florian Westphal brought to the table status on some open/pending work for mptcp option matching, systemd integration and finally interfacing from nft with cgroupv2. I was unable to participate in the talk for the first two items, so I cannot comment a lot more. On the cgroupv2 side, several options were evaluated to how to match them, identification methods, the hierarchical tree that cgroups present, etc. We will have to wait a bit more to see how the final implementation looks like. Also, Florian presented his concerns on conntrack hash collisions. There are no real-world known issues at the moment, but there is an old paper that suggests we should keep and eye on this and introduce improvements to prevent future DoS attack vectors. Florian mentioned these attacks are not practical at the moment, but who knows in a few years. He wants to explore introducing RB trees for conntrack. It will probably be a rbtree structure of hash tables in order to keep supporting parallel insertions. He was encouraged by others to go ahead and play/explore with this. Phil Sutter shared his past and future iptables development efforts. He highlighted fixed bugs and his short/midterm TODO list. I know Phil has been busy lately fixing iptables-legacy/iptables-nft incompatibilities. Basically addressing annoying bugs discovered by all ruleset managers out there (kubernetes, docker, openstack neutron, etc). Lots of work has been done to improve the situation; moreover I myself reported, or forwarded from the Debian bug tracker, several bugs. Anyway I was unable to attend this talk, only learnt a few bits in the following sessions, so I don t have a lot to comment here. But when I was fully present, I was asked by Phil about the status of netfilter components in Debian, and future plans. I shared my information. The idea for the next Debian stable release is to don t include iptables in the installer, and include nftables instead. Since Debian Buster, nftables is the default firewalling tool anyway. He shared the plans for the RedHat-related ecosystem, and we were able to confirm that we are basically in sync. Pablo commented on the latest Netfilter flowtable enhancements happening. Using the flowtable infrastructure, one can create kernel network bypasses to speed up packet throughput. The latest changes are aimed for bridge and VLAN enabled setups. The flowtable component will now know how to bypass in these 2 network architectures as well as the previously supported ingress hook. This is basically aimed for virtual machines and containers scenarios. There was some debate on use cases and supported setups. I commented that a bunch of virtual machines connected to a classic linux bridge and then doing NAT is basically what Openstack Neutron does, specifically in DVR setups. Same can be found in some container-based environments. Early/simple benchmarks done by Pablo suggest there could be huge performance improvements for those use cases. There was some inevitable comparison of this approach to what others, like DPDK/XDP can do. A point was raised about this being a more generic and operating system-integrated solution, which should make it more extensible and easier to use. Stefano Bravio commented on several open topics for nftables that he is interested on working on. One of them, issues related to concatenations + vmap issues. He also addressed concerns with people s expectations when migrating from ipset to nftables. There are several corner features in ipset that aren t currently supported in nftables, and we should document them. Stefano is also wondering about some tools to help in the migration. A translation layer like there is in place for iptables. Eric Gaver commented there are a couple of semantics that will not be suitable for translation, such as global sets, or sets of sets. But ipset is way simpler than iptables, so a translation mechanism should probably be created. In any case, there was agreement that anything that helps people migrate is more than welcome, even if it doesn t support 100% of the use cases. Stefano is planning to write documentation in the nftables wiki on how the pipapo algorithm works and the supported use cases. Other plans by Stefano include to work on some optimisations for faster matches. He mentioned using architecture specific instruction to speed up sets operations, like lookups. Finally, he commented that some folks working with eBPF have showed interest in reusing some parts of the nftables sets infrastructure (pipapo) because they have detected performance issues in their own data structures in some cases. It is not clear how to best achieve it, how to better bridge the two things together. Probably the ideal is to generalize the pipapo data structures and integrate it into the generic bitmap library or something which can be used by anyone. Anyway, he hopes to get some more time to focus on Netfilter stuff begining with the next year, in a couple of months. Moving a bit away from the pure software development topics, Pablo commented on the netfilter.org infrastructure. Right now the servers are running on gandi.net, on virtual machines that are being basically donated to us. He pointed that the plan is to simplify the infrastructure. For that reason, for example, FTP services has been shut down. Rsync services have been shut down as well, so basically we no longer have a mirrors infrastructure. The bugzilla and wikis we have need some attention, given they are old software pieces, and we need to migrate them to be more modern. Finally, the new logo that was created was presented. Later on, we spent a good chunk of the meeting discussing options on how to address the inevitable iptables deprecation situation. There are some open questions, and we discussed several approaches. From doing nothing at all, which means keeping the current status-quo, to setting a deadline date for the deprecation like the python community did with python2. I personally like this deadline idea, but it is perceived like a negative push by other. We all agree that the current do nothing approach is not sustainable either. Probably the way to go is basically to be more informative. We need to clearly communicate that choosing iptables for anything in 2020 is a bad idea. There are additional initiatives to help on this topic, without being too aggressive. A FAQ will probably be introduced. Eric Garver suggested we should bring nftables front and center. Given the website still mentions iptables everywhere, we will probably refresh the web content, introduce additional informative banners and similar things. There was an interesting talk on the topic of nft table ownership. The idea is to attach a table, and all the child objects, to a process. Then, we prevent any modifications to the table or the child objects by external entities. Basically, allocating and locking a table for a certain netlink socket. This is a nice way for ruleset managers, like firewalld, to ensure they have full control of what s happening to their ruleset, reducing the chances for ending with an inconsistent configuration. There is a proof-of-concept patch by Pablo to support this, and Eric mentioned he is pretty much interested in any improvements to support this use case. The final time block in the final session day was dedicated to talk about the next workshop. We are all very happy we could meet. Meeting virtually is way easier (and cheaper) than in person. Perhaps we can make it online every 3 or 6 months instead of, or in addition to, one big annual physical event. We will see what happens next year. That s all on my side!

I was invited to attend the Netfilter Workshop 2017 in Faro, Portugal this week, so I m here with all the folks enjoying some days of talks, discussions and hacking around Netfilter and general linux networking. The Coreteam of the Netfilter project, with active members Pablo Neira Ayuso (head), Jozsef Kadlecsik, Eric Leblond and Florian Westphal have invited me to join them, and the appointment has happened today. You may contact me now at my new email address: arturo@netfilter.org This is the result of my continued contribution to the Netfilter project since several years now (probably since 2012-2013). I m really happy with this, and I appreciate their recognition. I will do my best in this new position. Thanks! Regarding the workshop itself, we are having lots of interesting talks and discussions about the state of the Netfilter technology, open issues, missing features and where to go in the future. Really interesting!

Great news! The Netfilter project has been elected by Google to be a mentoring organization in this year Google Summer of Code program. Following the pattern of the last years, Google seems to realise and support the importance of this software project in the Linux ecosystem. I will be proudly mentoring some student this 2017 year, along with Eric Leblond and of course Pablo Neira. The focus of the Netfilter project has been in nftables for the last years, and the students joining our community will likely work on the new framework. For prospective students: there is an ideas document which you must read. The policy in the Netfilter project is to encourage students to send patches before they are elected to join us. Therefore, a good starting point is to subscribe to the mailing lists, download the git code repositories, build by hand the projects (compilation) and look at the bugzilla (registration required). Due to this type of internships and programs, I believe is interesting to note the ascending involvement of women in the last years. I can remember right now: Ana Rey (@AnaRB), Shivani Bhardwaj (@tuxish), Laura Garc a and Elise Lennion (blog). On a side note, Debian is not participating in GSoC this year :-(

Last week we had an interesting Debian meeting in Seville, Spain. This has been the third time (in recent years) the local community meets around Debian. We met at about 20:00 at Rompemoldes, a crafts creation space. There we had a very nice dinner while talking about Debian and FLOSS. The dinner was sponsored by the Plan4D assosiation. The event was joined by almost 20 people which different relations to Debian:

• Debian users
• DDs
• Debian contributors
• General FLOSS interested people

I would like to thank all the attendants and Pablo Neira from Plan4D for the organization. I had to leave the event after 3.5 hours of great talking and networking, but the rest of the people stayed there. The climate was really good :-) Looking forward to another meeting in upcomings times! Header picture by Ana Rey.

Last week we finally ended with a proper Debian informal meeting at Seville.

A total amount of 9 people attended, 3 of them DDs (Aurelien Jarno, Guillem Jover, Ana Guerrero) and 1 DM (me).

The meeting started with the usual "personal references" round, and then topics ranged from how to get more people involved with Debian, to GSoC-like programs discussions, and some Debian anecdotes as well.

There were also talks about when and how future meetings should be.

This meeting was hosted by http://www.plan4d.eu/, thanks to Pablo Neira (Netfilter project head).

Some pics of the moment:

s vezes voc s quer um pouco mais de velocidade nos downloads do APT e n o tem muito como modificar muito a instala o do cliente. Duas dicas simples podem ganhar minutos preciosos: Coloque em algum dos /etc/apt.conf.d (sugiro criar o /etc/apt.conf.d/71parallel) a seguinte linha:
Acquire::Queue-Mode "host";
Isso faz com que o modo de queue do APT seja orientado ao host e n o ao tipo de URL. Dependendo dos seus sources, isso acelera mais do que o modo access padr o. A segunda dica um hack que encontrei h algum tempo em um blog que faz o download pr vio das URLs que ser o utilizadas na opera o do APT para o /var/cache/apt/archives usando xargs:
#!/bin/bash NBATCH=3
NPARALLEL=5 (apt-get -y --print-uris $@ egrep -o -e "http://[^\']+" xargs -r -l$ NBATCH -P$ NPARALLEL wget -nv -P "/var/cache/apt/archives/") && apt-get $@
Ajuste os par metros NBATCH e NPARALLEL e boa sorte.

There was a Debian meeting at Sevilla last week.

The meeting was meant to be informal, just to know each other, hang out and drink some beers. There are a several people involved or interested in Debian and FLOSS here, but we barely know in person.

The event was announced with more than 1 month of anticipation in several mailing list (debian lists, local lists and university lists as well) and there was about 14 people interested in the event who said it explicitly.

You can see the Wiki page I set: https://wiki.debian.org/DebianEvents/es/2015/SevillaMeetingOctober

From the 14 people, 3 contacted before the event to announce they won't attend. The lasting 11 people were supposed to attend :-) In the end, we were 4 people and 3 of us know each other beforehand.

The attenders:

• vejeta (Juan, perhaps the main supporter of the meeting, Debian user)
• Pablo Neira (Netfilter upstream project and Linux kernel maintainer)
• Javier Barroso (IT architect in the local goverment and Debian user)
• me (the only directly involved in the Debian project, I'm DM)

This is a picture of that moment:


The truth is that we had a very good afternoon, but I personally missed some more people.
I remember Ana Guerrero telling me that a meeting of just 4-5 is indeed a victory :-)

We will have to try again :-)

Ok, so I'm back in Mexico! This year, the best fare I found for travelling to spend the Winter^WSummer season with Regina's family had an oddity: I usually have a layover at either Santiago de Chile or Lima (Per ) of between 45 minutes and 2 hours, clearly less than enough to do anything. But this time, I had a massive 10 hours layover in Santiago. And spending 10 hours in an airport is far from fun. Specially when you have a good group of friends in town! I visited Chile in 2004 for Encuentro Linux (still before the time I had a digital camera: Those photos are all taken by Martin Michlmayr), and I have stayed in touch with a group of systems administrators since then. So, I mailed the list, and we managed to get eight people to have lunch together. In the order we appear in the photo:

• Victor Hugo dos Santos
• Mauricio Troncoso
• lvaro Herrera
• Ricardo Lemus
• Marcelo Riquelme
• Carlos Sep lveda
• Gunnar Wolf
• Pablo Silva

Some of them, even living in the same city, had never met in person before So, of course, we had a table reserved at the restaurant to the name of Dennis Ritchie. And having had nice, fun, sometimes-technical talks... Well, a tiny bit of his spirit was there. Of course, we can only trust he was there, as no Ouija boards were used and no null pointers were dereferenced (just to make sure not to disturb him). Victor Hugo and lvaro took me for a short Santiago city trip before lunch, we had a very nice time. Thanks! :-)

This is my monthly summary of my free software related activities. If you re among the people who made a donation to support my work (147.56 , thanks everybody!), then you can learn how I spent your money. Otherwise it s just an interesting status update on my various projects. The Debian Administrator s Handbook I spent a good chunk of December on the book. First finalizing the English version and getting it out (BTW, just for the launch, there s a 10% discount on the paperback that lasts only until January 9th!). Then working on updating the French translation. Eyrolles will publish a new edition of the French book based on this translation. Expect some further news about this during January! Debian France I contributed to many discussions within Debian France. Starting with a complaint that most events are organized in Paris, I proposed to map the location of Debian France members. We added new fields in the membership management page so that members can add their GPS coordinates and Fr d ric Decou made some experiments with Openstreetmap. Someone else (Kiriarat) volunteered to write the required glue code. A manual map is currently maintained on the website. In the discussions about the setup of the Debian France shop, I suggested to update our logo with a nicer looking one. We got a few suggestions and after further discussions with Alexandre Delano and Sylvestre Ledru, we organized a small contest to entice designers to submit a logo proposal to us (the winner earns a set of Debian goodies). We got 46 proposals (see my favorite on the right)! The board is currently pre-selecting the logos and setting up the final vote for our members. The winner shall be announced at the end of the upcoming mini-debconf in Paris. I also continued the work to finalize new bylaws and new internal rules. They shall be adopted during the next general assembly which will happen during the mini-debconf. Misc Debian Work WordPress maintenance. I mentored Pablo Vasquez to do his first small contribution to the WordPress packaging. I really appreciate this but he s not yet ready to assume maintenance of a big package like WordPress on his own. I got multiple other offers of help and pinged them all while filing #733726 to coordinate the work on the new upstream version. But I got no reply Handing over packages to new maintainers is hard Init system discussion. The technical committee has the hard task of picking the default init system that will replace the traditional System V init (see #727708). I followed this huge discussion closely and contributed a bit where I add something meaningful to say. Final decision is expected sometimes in January. FWIW, I share entirely Russ Allbery s point of view in those discussions. I have been running systemd on some of my computers for a few months already. Fixing lxc in stable. The lxc package in stable has a non-working debian template. I really dislike documenting that things are broken so instead of doing that in the Debian Administrator s Handbook, I opted to do something about it. I prepared a non maintainer upload for stable (see #680469 for the problem and #732358 for the stable update request). Misc stuff. I sponsored a tcpdf upload. I filed an enhancement request on Publican to have it keep processing instructions present in translations. I uploaded new versions of publican-librement and debian-handbook. I filed #732678 against git-buildpackage because it failed to properly call lintian when given the -A dpkg-buildpackage argument. Thanks See you next month for a new summary of my activities.

No comment Liked this article? Click here. My blog is Flattr-enabled.

Just found out that I was cited academically for the first time: Pablo Buiras and Alejandro Russo s paper Lazy Programs Leak Secrets at NordSec2013 builds upon my work dup Explicit un-sharing in Haskell , which I had submitted to last year s Haskell symposium and Haskell Implementers Workshop, but eventually only published on arXiv.

My parents will soon be moving to a smaller home, so they are digging up a lot of stuff of my sister and mine past. Among my stuff, they just sent me my first computer (which was, of course, the first computer of my father s company I was using in the spare time). I couldn t believe they kept that. It was an Unitron Apple ][ 64K!! I just had it cleaned and took this picture: Due to the closed informatics market Brazilians were subject to at the time, it came with a full set of manuals in Portuguese which taught me how to code in Basic (I was too young to learn English at the time) Interesting how a bad policy like that can result in a Good Thing sometimes. Is it just me or does this picture made you nostalgic also?

Yesterday I was discussing in an online board how to break a decision deadlock in life. There are real deadlocks, but I don t think they are very frequent most of the time, doing a pros and cons analysis is enough to decide what to do. Sometimes our judgement is impaired by lack of objectivity or by our inability to see things from a different point of view (it s hard to think straight when everything seems to be falling apart around you); talking to a friend or relative can help in these situations. But there are times when nothing helps. When you are really stuck and nothing seems to break the deadlock. At these times I give it one or two days, sleep on the issue and if I cannot come up with a decision I assume the alternatives are equivalent to me and just flip a coin. Of course, this will do if you can postpone the decision, giving yourself (and your inner self) time to decide on a course-of-action. But is there some way to speed up the process? During the discussion, someone came up with a rather smart quote by Rothstein character in Boardwalk Empire TV series:

Flip a coin. When it s in the air, you ll know what side you re hoping for.

I found it an interesting way to give your inner self an ultimatum: decide or luck will decide instead. I ve never did it like that, for I would not flip a coin unless it s my last resort. Being such a clever psychological idea, I doubted it originated in the TV series itself, so I went on pursue of the original idea. I found a Danish poet and mathematician called Piet Hein, who wrote a poem about it circa 1969:

A PSYCHOLOGICAL TIP Whenever you re called on to make up your mind,
and you re hampered by not having any,
the best way to solve the dilemma, you ll find,
is simply by spinning a penny.
No not so that chance shall decide the affair
while you re passively standing there moping;
but the moment the penny is up in the air,
you suddenly know what you re hoping.

And also, there are a Donald Duck comic called Flip Decision circa 1953 that introduces Flipism philosophy, which supports a rather radical anecdotal variant: make all decisions by flipping a coin. Piet Hein or Rothstein character idea is much better than Flipism, of course. Does anyone knows any older sources of the same idea?

Reading about Michael Stapelberg s codesearch I bet a lot of people had the same idea. I just had to post a screenshot of it: It seems we have a lot to fix

Happy 19th birthday, Debian! The Debian project is 19 years old now. Following Francesca's invitation (and Rapha l's lead, and using Leandro's image, collaboratively as it always happens here), I will tell a bit of my memories: How I got to Debian. I am a Debian user since ~2000, and a Debian Developer since April 2003. But, just as Rapha l's, my history must go somewhat further back in time. In 1992, I got my first 1200bps modem, and almost immediately became an avid BBS user (what's that? Javier Matuk talks [in Spanish] about BBSes in his newspaper column back in 1994). By mid 1993 I started operating my own BBS, CatarSYS. One of the key points that defined CatarSYS is that my focus was large-scale communication. I started connecting to several BBS networks, allowing messages to be relayed to distant people, mainly in the USA and Spain, and getting some feeds that could be seen as the poor man's Usenet. At some point during the year I kept CatarSYS going, I got connected through a strange set of gateways to pure gold: A UUCP feed! This means, during some months, I operated the first (free, hobbyist) service that offered its users a free Internet mail address in Mexico. Yes, it was completely different to what we are used to today. I tried to connect to my provider at least three times a week, but this meant less than one week turnover time for messages sent to people anywhere in the world! But, back to Debian: Via this UUCP feed, I also got some real Usenet newsgroups Including several on the comp.os category. I remember reading about Linux back then, and learning some commands, but didn't really get hooked into it. I was in Israel from July 1994 to June 1995, doing completely non-computer-related tasks. Came back in 1995, and due to my father being an academic, got dialup internet access at home. WOW, *real* Internet! It didn't take me long to start downloading Linux information and floppy images. One failed after another. But before the end of the year, I found in a bookshop a book (that included a CD-ROM) called "Build your own web server with Linux". WOW again Remember this was still 1995! I bought it, and shortly afterwards, I had a Slackware system (Linux kernel 1.0.9) running. That meant many sleepless nights full of joy and frustration (as getting hardware to work was cloe to impossible). By 1996, I got (within one week) my two first real jobs: A systems administrator at a small ISP and a highschool teacher. At the ISP, I got a spare computer to play with Linux, as of course the Big Server was running with Windows NT 3.51. Poor little machine... By then I was already a part of the Mexican Linux User Group. This group had just printed a batch of Linux CDs RedHat 4.0. This was the first release that really made me happy and allowed me to do good work. Together with a friend I took to work with us, Juan Pablo Romero, we installed over a weekend a full replacement for our buggy NT machine, in much cheaper hardware. Of course, Linux was nowhere near corporate-recognition, and our project remained a project, not touching the Windows machine. Anyway... Several years passed, and I was happy with my RedHat choice. I won't mention the milestones and job changes, as it would get boring and leave the point completely aside. By the year 2000, I was quite more involved with the LUG, as well as with the computer security group in DGSCA-UNAM. I became also an OpenBSD user, and had got so hooked up in free software that I felt the need to collaborate: To be a little part of one of those Big Projects that had given me so much. But which one? I have never been much of a programmer Yes, I can solve my everyday needs and have fun with it, and sometimes a bit beyond that. I enjoy programming. But all of my projects have begun little and stayed little. I wanted to join OpenBSD, as it was a community I really believed in, but given my skillset (and given a flame-prone, aggressive developer community), I lost motivation to do so. By 2000, I had also lost faith in RedHat. I don't have the exact dates, so I might be some months off But after RedHat's IPO, I felt a sharp change. Version 7.0 was really demotivating It tried to offer a polished desktop experience, but was really buggy, unstable, and full of bad decisions. In Mexico, Pepe Neif had taken up the job of making a derivative distribution of RedHat (called LinuxPPP), pressing hundreds of CDs and making a teaching program I was part of several times. Talking with Pepe (who continued to release based on RedHat 6), he told me he was interested in switching over to become a Debian-based distribution, but the job of migrating his installed base made the project stall LinuxPPP reached only version 6.4. But I installed Debian in early 2000, and loved it. I started getting familiar with its social philosophy and foundation documents at the same time I started migrating my servers from RedHat to Debian This must have been by Spring 2000, as I installed Potato while it was frozen but not yet stable. By January 2002 I applied for NM. My process took a long time, as my AM got MIA when he had already approved me (but before sending the AM report), so basically I had to go through AM twice And by April 16, 2003, I got accepted as a DD. Contrary to what is acceptable today, I requested the full process to be done before starting to maintain any packages, as I didn't want to bother people with package sponsorship requests, so my whole process was done evaluating packages I would eventually upload. Since becoming a DD, my main involvement in the project has been in packaging groups (I was a pkg-perl founder and member for many years, and am currently working in the pkg-ruby-extras group). But, as I said, my main strength is not programming So my main involvement in Debian has been more social than technical: I have been a DebConf organizer since 2005, a very interesting, stressing, rewarding and (for some months) time-demanding role, and since 2009 I am part of the keyring maintainence team, which is much easier workload, although carries important ramifications. So, after 19 years of Debian, and after nine years of me being part of it, Debian is clearly my strongest link to the Free Software community, a project I have grown to love and whose way of being I share and enjoy studying and explaining. And it is a technically excellent product, and a great place to start and keep learning both about how every aspect and layer of an operating system works, and how human-to-human interaction works in such a diverse, almost impossible environment happens. Congratulations, Debian!

Attachment	Size
debian-19_500.png	149.81 KB

A new neighbourhood to explore today: the South-West/West area. Indeed, my original plan was going towards Lagunas de Nejapa and Asososca. However, I now understood that such non urban areas in Managua are almost inaccessible. It sound like walking and hiking in the nature is not something that urban inhabitants of Managua do often. So, in short, these places are....just impossible to go to. Anyway, I wanted to see this, just in case. As a consequence, I ended heading westward from Hotel Seminole through Avenida Miguel Obando Y Bravo (the busy highway close to the hotel, where we boarded the Day Trip buses). Running along this one is not a bad thing as it is not that busy, particularly at 05:45..:-) After crossinb Pista de la Unan that goes north towards the lake, I went 200m east then headed north up to reach the very busy Pista Juan Pablo II (or Pista de la Resistencia). For those who went to the day trip, this is the highway we went through at the beginning of the journey to Leon. It sounds crazy to run along a busy highway but:

• it was not that busy at that time
• this is the only way to not get lost in the barrios as we'll see later on..:-)

I followed that one during about 4km until it ends facing a cone-style mountain, about 150m high (former volcano crater?) After that long run straight, I ended at a big crossing, where the highways go either north or south....but a small street continues westward and is apparently going around the Laguna de Nejapa, at least according to Google Maps. However, there is indeed, as too often here, a barrier (which OSM would have told me, indeed). Hence, disappointed, I only could go back to the busy streets. I however decided that I would NOT come through the same way but rather try to run in smaller streets. This is where the problem lies. Indeed, Managua "barrios" are not always connected by streets to the large and busy streets that surround them. This is mostly because several rivers run south to north, towards the lake. And these are canalyzed to avoid floodings, which means there are not that many bridges to cross them. So, it often ends that a barrio is only connected on one or two of its sides, which makes travelling through them particularly difficult and puzzling (especially going in the east-west directions). So, I happened to search my way many times in these places, particularly in Barrio Pablo Sexto where the rivers directions are really confusing..:-) I finally had no other choice than going down to the big Pista Juan Pablo II and come back the same way to the hotel. The final result is a 15km run in 1h20. Not that a bad pace in these weather conditions. GPS trace

I was looking for an excuse to try Zotero and the perfect opportunity appeared when I got a whole lot of references to group for a month of Magnetic Ressonance studies I am currently taking. I was also pleased to notice it is packaged to Debian. I am used to note-taking software. Back when I used a Palm m130 (and a Treo 650), I managed a lot of Memos I eventually migrated to Note-Everything in my current Android phone. Zotero, unfortunatelly, is not interfaceable with my phone (or I was still unable to figure out how to do so), but it s powerful in managing references beyond simple note-taking. Is anyone using Zotero in a more ambitious way? I ve read about people using it to keep large researchs to support fiction and non-fiction book-writing I also watched some YouTube videos on it. As far as I went with it, Zotero might become an important piece in my toolbox wrt reference keeping, so I was just trying to figure out how many other niches it can fill

Just for reference, this is really useful: Update Apr 20, 2012 @ 16:54: As pointed in a comment by Timo Juhani Lindfors, if some_command exits early and the interval is long, another process can reuse its process number and get killed once the sleep runs out. Does anybody know a better way of doing that without using timeout from coreutils (better yet: using just bash)?

You know the drill. Official announcement is here (or here in portuguese). Anybody planning to drop by FISL13 should submit a key.

OK, this is not another post on how to use Mutt and Gmail. This is just to comment on a feature I found in Mutt that was not obvious, and that helped me to stop running my own anti-spam tool. So, for a number of reasons, my company stop filtering spams. I was setting up dspam to take over that job when I decided that it was just too much pain for a single account. Besides, although I am spammed a lot, I would never possibly be more efficient than Gmail anti-spam, given the load of emails their users classify everyday. I am not migrating my old emails over to Gmail, though. And I am pretty comfortable with my current email work-flow I am simply not going to use a webmail (even one as powerful as Gmail). OK, I am using GNOME 3 after being a Fluxbox and Bluetile user, but everything has a limit But how to keep the best of both worlds? And, more important, how to do that with minimum disruption of what I already have (my own IMAP server and Mutt managing my account there as spoolfile)? The answer is a little known trick using the mailboxes directive in .muttrc. This directive accepts a fully-qualified imap mailbox address. So I just added something like: and added some shortcuts to save email from my inbox to that mailbox (the same as train-as-spam) and to rescue email from it (the same as train-as-ham): and that was it. In my IMAP machine I got a fetchmail downloading emails from Gmail s INBOX so I can get trained-as-ham and new emails (all emails arrive first in my Gmail account) into my IMAP server. All my sieve rules are in place and nothing changed in my email work-flow. It s been working flawlessly for a week now. The only drawbacks are (1) Gmail knowing everything that arrives to me (not a big deal, since unencrypted emails aren t private anyway), and (2) not getting the spam-count once Mutt is run: I have to change into that mailbox to log-in to Gmail. Update: Mar 30, 2012 @ 18:15: I just found out that drawback number (2) above can be fixed by adding the following to .muttrc: