[CentOS] Sendmail failing on home machine

Christopher Chan christopher at ias.com.hk
Wed Nov 7 06:52:47 UTC 2007

Peter Loron wrote:
> I have a CentOS 5 machine at home, behind a NAT gateway. Among other 
> things, I'm running mdadm in monitor mode to alert me to RAID failures. 
> I want it to send messages to my main email address. Any messages I send 
> from the home CentOS box to that email address are being rejected with 
> this error:
> Deferred: 451 Could not complete sender verify callout

This is not sendmail failing.

> My understanding is that the destination mail server is trying to 
> connect back to the source email host via SMTP as an anti-spam check and 
> is failing.
> My external IP is set up with a dynamic DNS entry, so I guess I could 
> set up an MX record and actually receive mail on the home box, but I 
> don't want to deal with the security issues or the spam.
> Any suggestions for allowing sendmail-dependent apps running on the home 
> machine to be able to send mail?

Nothing to do with your ip. Just use an email address that Google can 
verify and again, it has NOTHING to do with sendmail.

More information about the CentOS mailing list