[CentOS] Sendmail Masquerade

Mon Aug 20 15:22:42 UTC 2012
Les Mikesell <lesmikesell at gmail.com>

On Mon, Aug 20, 2012 at 5:31 AM, Ken Smith <kens at kensnet.org> wrote:
> Hi All,
> I'm usually quite good with sendmail on Centos 5.8 but I must have
> missed something here. I've not done this before but, I want to set
> sendmail so that its outgoing mail appears to come from the domain of
> the network it lives on. Its real hostname is server2.domain.co.uk ( the
> domain bit is substituted for this post) and I want it to send as
> domain.co.uk, that is really valid, but the specific host
> server2.domain.co.uk does not have an A record and other mailservers
> reject its outgoing mail because server2.domain.co.uk does not resolve.
> But with these settings in sendmail.mc it still sends as
> server2.domain.co.uk if I simply type "mail -s test kens at kensnet.org"
> into bash.
> MASQUERADE_AS(`domain.co.uk')dnl
> FEATURE(masquerade_envelope)dnl
> FEATURE(masquerade_entire_domain)dnl
> MASQUERADE_DOMAIN(domain.co.uk)dnl
> (Yes I have done the m4 bit and restarted sendmail)
> If I telnet to sendmail on port 25 and manually send as
> username at domain.co.uk it has the right "from" address.
> So what have I missed?

Are you doing the test that fails as the 'EXPOSED_USER' in sendmail.mc
(i.e. root)?  That is for intentional exceptions to MASQUERADE_AS so
you can tell where system type messages from cron jobs, etc. originate
if you send everything to a mail hub.

  Les Mikesell
     lesmikesell at gmail.com