Racker Hacker Words of wisdom from a server administrator

Disabling SSLv2 in Dovecot is relatively easy:
ssl_cipher_list = ALL:!ADH:!LOW:!SSLv2:!EXP:+HIGH:+MEDIUM
# openssl ciphers -v ‘ALL:!ADH:!LOW:!SSLv2:!EXP:+HIGH:+MEDIUM’
DHE-RSA-AES256-SHA SSLv3 Kx=DH Au=RSA Enc=AES(256) Mac=SHA1
DHE-DSS-AES256-SHA SSLv3 Kx=DH Au=DSS Enc=AES(256) Mac=SHA1
AES256-SHA [...]

This is one of Exim’s more cryptic errors:
Mar 29 11:22:52 114075-web1 postfix/smtp[20589]: 9E0142FC589: to=, relay=somehost.com[11.11.11.11], delay=147966, status=deferred (host somehost.com[11.11.11.11] said: 451 Could not complete sender verify callout (in reply to RCPT TO command))
When you send e-mail to an Exim server with a sender verify callout enabled, the Exim server will connect back into your server [...]

If you need to change the hostname that Sendmail announces itself as, just add the following to sendmail.mc:
define(`confDOMAIN_NAME’, `mail.yourdomain.com’)dnl
And, to add additional stuff onto the end of the line:
define(`confSMTP_LOGIN_MSG’,`mailer ready’)dnl

If you find that the time zones are hopping around in your syslog output, there is an open bug with Redhat about it and the release is still pending.

If you have too many files to remove, try this trick:
find . -name ‘*’ | xargs rm -v