Public bug reported: Binary package hint: exim4-daemon-light
When Exim is first installed (on Dapper), mail delivery times out like this: ch...@fen-fw:~$ sudo exim -qf -v -v LOG: queue_run MAIN Start queue run: pid=30436 -qf delivering 1LbXpS-0007T6-ED (queue run pid 30436) R: system_aliases for r...@fen-fw.aptivate.org R: smarthost for hid...@aptivate.org T: remote_smtp_smarthost for hid...@aptivate.org Connecting to net-mail.aptivate.org [80.248.178.172]:25 ... connected SMTP<< 220 mail.aidworld.org ESMTP Exim 4.62 Mon, 23 Feb 2009 10:21:59 +0000 SMTP>> EHLO fen-fw.aptivate.org SMTP<< 250-mail.aidworld.org Hello fen-fw.aptivate.org [217.155.111.90] 250-SIZE 52428800 250-PIPELINING 250-AUTH PLAIN LOGIN 250-STARTTLS 250 HELP SMTP>> STARTTLS SMTP<< 220 TLS go ahead (hangs for a long time here) The problem is complex: * Dapper uses a kernel version which has poor entropy gathering (see Debian bug #343085). /dev/random is usually nearly empty, as my Munin graphs show, and my /proc/sys/kernel/random/entropy_avail is (was) usually below 200 bytes * exim4 is linked with GnuTLS rather than OpenSSL (see Debian bug #343085) * GnuTLS makes much less efficient use of available entropy (see Debian bug #343085) * Exim needs to generate a DH parameters cache file before TLS will work (/var/spool/exim4/gnutls-params, see Debian bugs #343085 and #338319) * This file is not generated on installation, but by a mail-sending process (see Debian bug #338319) * Due to low entropy and GnuTLS wastefulness, this file takes a very long time to generate (e.g. hours/days) * Until generated, exim4 cannot send mail, hanging forever as above * This file is also deleted by /etc/cron.daily/exim4-base, UNLESS the gnutls-bin package is installed, therefore the problem will recur daily (see Debian bug #338319) Possible workarounds are: * replace /dev/random with link to /dev/urandom (has security implications) * install an entropy gathering daemon. I installed rng-tools, unexpectedly it works on my hardware, my entropy pool is back up at 4000 now (i.e. full). this will probably not work for everyone * wait for exim to generate the gnutls-params itself (every day) and accept that mail will hang until then * install gnutls-bin * generate gnutls-params immediately after installation I'd recommend making exim4-config depend on gnutls-bin, AND generate the gnutls-params file during package installation so that the admin is not mystified by an installed but apparently non-working exim4 package. Description: Ubuntu 6.06.2 LTS Release: 6.06 ch...@fen-fw:~$ apt-cache policy exim4 exim4-daemon-light libgnutls12 libgcrypt11 exim4: 4.60-3ubuntu3.1 exim4-daemon-light: 4.60-3ubuntu3.1 libgnutls12: 1.2.9-2ubuntu1.2 libgcrypt11: 1.2.2-1 ** Affects: exim4 (Ubuntu) Importance: Undecided Status: New -- Exim hangs on delivering mail, lack of entropy for TLS https://bugs.launchpad.net/bugs/333257 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs