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Episode 076: Time for a Change


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Strange timer bug in FreeBSD 11

  • Peter Wemm wrote in to the FreeBSD -CURRENT mailing list with an interesting observation
  • Running the latest development code in the infrastructure, the clock would stop keeping time after 24 days of uptime
  • This meant things like cron and sleep would break, TCP/IP wouldn't time out or resend packets, a lot of things would break
  • A workaround until it was fixed was to reboot every 24 days, but this is BSD we're talking about - uptime is our game
  • An initial proposal was adding a CFLAG to the build options which makes makes signed arithmetic wrap
  • Peter disagreed and gave some background, offering a different patch to fix the issue and detect it early if it happens again
  • Ultimately, the problem was traced back to an issue with a recent clang import
  • It only affected -CURRENT, not -RELEASE or -STABLE, but was definitely a bizarre bug to track down

An OpenBSD mail server

  • There's been a recent influx of blog posts about building a BSD mail server for some reason
  • In this fancy series of posts, the author sets up OpenSMTPD in its native OpenBSD home, whereas previous posts have been aimed at FreeBSD and Linux
  • In addition to the usual steps, this one also covers DKIMproxy, ClamAV for scanning attachments, Dovecot for IMAP and also multiple choices of spam filtering: spamd or SpamAssassin
  • It also shows you how to set up Roundcube for building a web interface, using the new in-base httpd
  • That means this is more of a "complete solution" - right down to what the end users see
  • The series is split up into categories so it's very easy to follow along step-by-step

How DragonFlyBSD uses git

  • DragonFlyBSD, along with PCBSD and EdgeBSD, uses git as its version control system for the system source code
  • In a series of posts, Matthew Dillon (the project lead) details their internal setup
  • They're using vanilla git over ssh, with the developers' accounts set to git-only (no shell access)
  • The maintainers of the server are the only ones with shell access available
  • He also details how a cron job syncs from the master to a public box that anyone can check out code from
  • It would be interesting to hear about how other BSD projects manage their master source repository

Why not try PCBSD?

  • ITwire, another more mainstream tech site, published a recent article about switching to PCBSD
  • They interview a guy named Kris that we've never heard of before
  • In the article, they touch on how easy it can potentially be for Linux users looking to switch over to the BSD side - lots of applications are exactly the same
  • "With the growing adoption of systemd, dissatisfaction with Linux has reached proportions not seen in recent years, to the extent that people have started talking of switching to FreeBSD."
  • If you have some friends who complain to you about systemd all the time, this might be a good article to show them

Interview - Henning Brauer - / @henningbrauer

OpenNTPD and its portable variant

News Roundup

Authenticated time in OpenNTPD

  • We recorded that interview with Henning just a few days ago, and it looks like part of it may be outdated already
  • While at the hackathon, some developers came up with an alternate way to get authenticated NTP responses
  • You can now add an HTTPS URL to your ntpd.conf in addition to the time server pool
  • OpenNTPD will query it (over TLS, with CA verification) and look at the date sent in the HTTPS header
  • It's not intended to be a direct time source, just a constraint to keep things within reason
  • If you receive regular NTP packets that are way off from the TLS packet, those will be discarded and the server(s) marked as invalid
  • Henning and Theo also weigh in to give some of the backstory on the idea
  • Lots more detail can be found in Reyk's email explaining the new feature (and it's optional of course)

NetBSD at Open Source Conference 2015 Oita and Hamanako

  • It's been a while since we've featured one of these trip reports, but the Japanese NetBSD users group is still doing them
  • This time the conferences were in Oita and Hamanako, Japan
  • Machines running NetBSD included the CubieBoard2 Allwinner A20, Raspberry Pi and Banana Pi, Sharp NetWalker and a couple Zaurus devices
  • As always, they took lots of pictures from the event of NetBSD on all these weird machines

Poudriere in a jail

  • A common question we get about our poudriere tutorial is "how do I run it in a jail?" - this blog post is about exactly that
  • It takes you through the networking setup, zpool setup, nginx setup, making the jail and finally poking the right holes in the jail to allow poudriere to work its magic

Bruteblock, another way to stop bruteforce

  • We've mentioned a few different ways to stop ssh bruteforce attempts in the past: fail2ban, denyhosts, or even just with pf's built-in rate limiting
  • Bruteblock is a similar tool, but it's not just for ssh logins - it can do a number of other services
  • It can also work directly with IPFW, which is a plus if you're using that as your firewall
  • Add a few lines to your syslog.conf and bruteblock will get executed automatically
  • The rest of the article takes you through the different settings you can configure for blocking

New iwm(4) driver and cross-polination

  • The OpenBSD guys recently imported a new "iwm" driver for newer Intel 7260 wireless cards (commonly found in Thinkpads)
  • NetBSD wasted no time in porting it over, giving a bit of interesting backstory
  • According to Antti Kantee, "it was created for OpenBSD by writing and porting a NetBSD driver which was developed in a rump kernel in Linux userspace"
  • Both projects would appreciate further testing if you have the hardware and can provide useful bug reports
  • Maybe FreeBSD and DragonFly will port it over too, or come up with something that's partially based on the code

PCBSD current images

  • The first PCBSD -CURRENT images should be available this weekend
  • This image will be tagged 11.0-CURRENTFEB2015, with planned monthly updates
  • For the more adventurous this will allow testing both FreeBSD and PCBSD bleeding edge


Mailing List Gold


Comparison of ways to securely tunnel your traffic

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