Have a subnet protected by a firewall. Firewall Network Address Translation
(NAT) is turned on. There is no DNS on the protected subnet, but the
firewall is running Split / Dual DNS so it can route traffic in conjunction
with the ISP's DNS.
The firewall is proxing SMTP traffic to/from a 'sendmail' host on the
protected subnet. I presume since the sendmail host can not "see" outside
the firewall to send / receive mail (NAT, Split DNS), it should be
configured to rely completely on the ISP's SMTP server for all email.
Correct? Are there any specifics I need to know regarding this type of
sendmail / SMTP set-up?
Someone who does not know a lot about sendmail; :-)