Exim Entropy

While trying to get exim4 using TLS I noticed an odd problem. For some reason /dev/random was not generating a lot of output due to a lack of entropy. I do not fully understand the problem but it meant that exim4 was being blocked when generating the RSA key. I tried changing from a 2.4.32 kernel to a 2.6.16.27 kernel and this seemed to generate more random data but it still wasn't sufficient.

I resorted to editing my

/etc/cron.daily/exim4-base

commenting out the last line that deletes

/var/spool/exim4/gnutls-params

I then ran

find / -type f | xargs cat > /dev/null

to generate a lot of noise on the system.

hal:~# swaks -a -tls -q HELO -s localhost -au harry
Password:
=== Trying localhost:25...
=== Connected to localhost.
<- 220 hal.vm.bytemark.co.uk ESMTP Exim 4.50 Mon, 27 Nov 2006 14:34:53 +0000
-> EHLO hal.vm.bytemark.co.uk
<- 250-hal.vm.bytemark.co.uk Hello localhost [127.0.0.1]
<- 250-SIZE 52428800
<- 250-PIPELINING
<- 250-STARTTLS
<- 250 HELP
-> STARTTLS

By Harry on November 27, 2006 3:25 PM | Permalink | Comments (0)