My friendly neighborhood Solaris Sendmail admin at work noted that when one telnets to a sendmail server:
% telnet domain.com 25
you will get a reslt that looks kinda like this:
Connected to domain.com.
Escape character is '^]'.
220 domain.com ESMTP Sendmail 8.12.2/8.12.2; Sat, 11 Jan 2003 09:33:56 -0500 (EST)
which gives potentil hackers two clues: WHAT you are running and WHAT version. This (he said) is a *BAD* thing.
He suggested editing the sendmail.cf file and changing the privacy options to:
# privacy flags
whichs sounds like a GOOD thing, however doing so and restarting sendmail (sudo kill -HUP [PID]) or even running the update scrip seems to have no effect.
amigasteve (at) comcats (dot) net