Trying to understand why mail is not being sent ?
If your tail -f /var/log/maillog logs are showing something like this:
Aug 30 22:43:06 netman sendmail: starting daemon (8.14.4): SMTP+queueing@01:00:00 Aug 30 22:43:06 netman sm-msp-queue: starting daemon (8.14.4): queueing@01:00:00 Aug 30 22:43:11 netman sendmail: q7SIq1Kk011256: to=<email@example.com>, ctladdr=<firstname.lastname@example.org> (0/0), delay=2+04:51:10, xdelay=00:00:05, mailer=esmtp, pri=3720580, relay=alt4.jial-smtp-in.l.gogglee.com. [XX.125.142.26], dsn=4.0.0, stat=Deferred: alt4.jial-smtp-in.l.googglee.com.: No route to host
Try telnet-ing to the IP [XX.125.142.26] on port 25:
telnet XX.125.142.26 25
[root@netman ~]# telnet 18.104.22.168 25 Trying 22.214.171.124... telnet: connect to address 126.96.36.199: No route to host [root@netman ~]#
Check here to see if your server is blacklisted using this site:
There all you need to do is enter your external IP address and see if that is the issue.
If not remember if you are using dynamically assigned IPs there is a good chance that’s the issue try relaying through another server.