I recently upgraded the Postfix mail server from 2.3.8 to 2.4.0 on a Debian linux server that has a 2.4 kernel due to other applications that it has. I always check the bug reports before upgrading packages but I obviously missed Debian bug #417530, whose summary is Fatal error: “epoll_create: Function not implemented” using kernel 2.4 and postfix 2.4. Normally Debian’s APT package management system contains all the dependencies but it did not contain a dependency on kernel 2.6 for the new epoll() function, which can improve network socket performance.
After upgrading Postfix I tried sending an email but Thunderbird gave an error message so I checked the syslog on the server and discovered the that the /var/log/syslog contained the following error message: postfix/master[24312]: fatal: epoll_create: Function not implemented I searched for Postfix bugs using the Debian bugs by package search plugin for Firefox.
The solution is to revert to the Postfix 2.3.8 but that was not as straightforward as I thought. I hoped that there would be a revert to previous or similar option for the apt-get or dpkg commands but I could not find it. I tried telling it to install 2.3.8 but apt-get refused to install 2.3.8 as a newer version was already installed. I could not uninstall Postfix as several other packages are dependent on Postfix, including Bugzilla.
In the end I downloaded Postfix 2.3.8 from a Debian mirror as a .deb using wget and using dpkg to install it, not forgetting to do a dry-run first to check what dpkg would do.
dpkg –install –dry-run postfix_2.3.8-2+b1_i386.deb
dpkg –install postfix_2.3.8-2+b1_i386.deb
This time when I tried to send an email using Thunderbird it worked. The moral is to always check the bugs before installing and updating packages.
Debian search plugins for Firefox on mycroft.mozdev.org.