sendmail smart relay host

[Mark P]

Hi all,

I need help getting sendmail working. We have a
central mail gateway that I need to send all outbound
mail through. That server is mailgw.co.com
(172.16.1.3).

On the mail client (FBSD 4.8), I have
enable_sendmail="NO" and sendmail_submit_enable="YES"
in /etc/rc.conf. If I set DS (null) in
/etc/mail/submit.cf, mail is sent directly to the
remote mail host fine. If I set DS172.16.1.3 in
/etc/mail/submit.cf, I can't send mail at all.
Checking the /var/log/maillog I see:

Apr 21 16:37:58 box1 sendmail[774]: h3LKbsAs000774:
to=user at test.net, ctladdr=parsissn (1000/1000),
delay=00:00:04, xdelay=00:00:00, mailer=relay,
pri=30039, relay=172.16.1.3, dsn=5.1.2, stat=Host
unknown (Name server: 172.16.1.3: host not found)
Apr 21 16:37:58 box1 sendmail[774]: h3LKbsAs000774:
h3LKbsAt000774: DSN: Host unknown (Name server:
172.16.1.3: host not found)


In the bounced mail I see:


----- The following addresses had permanent fatal
errors -----
user at test.net
    (reason: 550 Host unknown)

   ----- Transcript of session follows -----
550 5.1.2 user at test.net... Host unknown (Name server:
172.16.1.3: host not
 found)


Can anyone see what I'm doing wrong? 172.16.1.3 has
both A and PTR records in DNS, so I wouldn't think
taht is it. I'm sure I've just got it config'd wrong.
Any suggestions?

Much thanks,
Mark

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