secure lmtp connection between sendmail and cyrus

[Marcus Schopen]

Am Sonntag, den 16.02.2014, 00:43 +0100 schrieb Marcus Schopen:
> Am Samstag, den 15.02.2014, 18:56 +0100 schrieb Marcus Schopen:
> > Hi,
> > 
> > I'm looking for a secure and stable way to connect sendmail (8.14.4) and
> > cyrus (2.4.12) in case of both hosts not running on the same machine or
> > in the same local secure subnet.
> > 
> > What is a practical way? An openvpn (tcp or udp?) connection between
> > sendmail and cyrus and starting lmtpd with -a option at the tunnel's
> > end?
> > 
> > Or a LMTPs connection with LMTP_AUTH, but couldn't find any good example
> > configs how to configure sendmail to use LMTP_AUTH und TLS to talk to
> > cyrus.
> 
> LMTP_AUTH connections via access
> 
> # client AUTH
> AuthInfo:IP "I:testuser" "P:test

> 
> and put testuser to lmtp_admins on cyrus side
> lmtp_admins: testuser
> 
> But this is still not secure of course. Would a openvpn or tinc tunnel
> be faster instead of a LMTPs connection?

TLS for lmtp connections between sendmail and cyrus seems to work out of
the box as soon as tls_cert_file, tls_key_file and tls_ca_file are set
on cyrus side and sendmail is configured with starttls and sasl. Nice!

But question is still if a permanent openvpn tunnel to an lmtpd started
with -a is faster than an authentication and starting tls for each
incoming email?

Ciao!