Villaver Family Blog » Debian http://www.villaver.org/wordpress Mon, 08 Aug 2011 20:42:13 +0000 en hourly 1 http://wordpress.org/?v=3.2.1 Java Plugin problem and workaround in Debian Squeeze http://www.villaver.org/wordpress/2009/12/24/java-plugin-problem-and-workaround-in-debian-squeeze/ http://www.villaver.org/wordpress/2009/12/24/java-plugin-problem-and-workaround-in-debian-squeeze/#comments Thu, 24 Dec 2009 21:45:21 +0000 Kagwang http://www.villaver.org/wordpress/?p=470 I use the Squeeze aka testing distribution of Debian Linux on my dual boot computer at home. After updating the packages yesterday I discovered that java applications including Tomcat and Java Webstart were unable to connect to the network.  I had no idea what was going on as I had not upgraded Java or Tomcat.  After a lot of searching through the logs and then the internet I found Debian Bug #560142 and Sun bug #6342561 describing the problem. Apparently, it is related to a change in IPv6 networking in the netbase package that causes Java applications to ignore IPv4 network connections, which is rather annoying.

Fortunately, there is a simple workaround for running servers:

echo 0 > /proc/sys/net/ipv6/bindv6only

You will also have to change the default value in /etc/sysctl.d/bindv6only.conf from 1 to 0 so that the value is used after a reboot.

This means that Java is able to connect to IPv4 servers.  Hopefully, this will be fixed soon but I'm glad to have found out what the problem was and to have a workaround.

Merry Christmas.

]]> http://www.villaver.org/wordpress/2009/12/24/java-plugin-problem-and-workaround-in-debian-squeeze/feed/ 0 Reverting to previous Postfix version due to bug #417530 http://www.villaver.org/wordpress/2007/04/15/reverting-to-previous-postfix-version-due-to-bug-417530/ http://www.villaver.org/wordpress/2007/04/15/reverting-to-previous-postfix-version-due-to-bug-417530/#comments Sun, 15 Apr 2007 10:51:29 +0000 Kagwang http://www.villaver.org/wordpress/2007/04/15/reverting-to-previous-postfix-version-due-to-bug-417530/ 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.

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