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I've recently setup a new backup server and have configured sendmail with a smart_relay_host

Except every email from the command line doesn't go anywhere. From mail.log:

Oct 3 14:32:52 **back01 sm-mta[16570]: p93DWqtC016568: to=<>, ctladdr= (0/0), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=120762, relay=, dsn=5.1.2, stat=Host unknown (Name server: host not found) Oct 3 14:32:52 ***back01 sm-mta[16570]: p93DWqtC016568: p93DWqtC016570: DSN: Host unknown (Name server: host not found)

DNS is working correctly on this box. I can do forward and reverse lookups.

I can also telnet to the mail relay and send a message that way.

I'm stumped, any suggestions?

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Name server: host not found tell me, what this NS ( can't resolve name for your smart-relay, isn't it? Just try to resolve host from SMART_HOST definition (and connect to it later)

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