I was migrating some mail today to a new mailserver, i needed to test mail quickly.

So I run this on an external server

echo "Hello world" | mail -s "meh" [email protected]

I then ran an tail -f /var/log/mail.log on my local mail server

tail -f /var/log/mail.log

Mar 10 17:42:22 mymail-7-wheezy postfix/cleanup[14592]: 9EF95D42A5: message-id=<[email protected]>
Mar 10 17:42:22 mymail-7-wheezy postfix/qmgr[4691]: 9EF95D42A5: from=, size=1097, nrcpt=1 (queue active)
Mar 10 17:42:22 mymail-7-wheezy postfix/virtual[14604]: 9EF95D42A5: to=, relay=virtual, delay=0.01, delays=0/0/0/0, dsn=2.0.0, status=sent (delivered to maildir)
Mar 10 17:42:22 mymail-7-wheezy postfix/qmgr[4691]: 9EF95D42A5: removed
Mar 10 17:42:22 mymail-7-wheezy amavis[14463]: (14463-01) Passed CLEAN {RelayedOpenRelay}, [37.1.1.1]:46386 [37.1.1.1]  -> , Queue-ID: 347DDD429D, Message-ID: <[email protected]>, mail_id: Y9fimRqJrWtV, Hits: 1.693, size: 650, queued_as: 9EF95D42A5, 1448 ms
Mar 10 17:42:22 mymail-7-wheezy postfix/smtp[14596]: 347DDD429D: to=, relay=127.0.0.1[127.0.0.1]:10024, delay=1.5, delays=0.01/0/0.01/1.4, dsn=2.0.0, status=sent (250 2.0.0 from MTA(smtp:[127.0.0.1]:10025): 250 2.0.0 Ok: queued as 9EF95D42A5)
Mar 10 17:42:22 mymail-7-wheezy postfix/qmgr[4691]: 347DDD429D: removed

As we can see email is working rather nicely after my DNS updates!

A good way to test this.