Plesk 11 - Postfix not sending any smtp emails

[whnunlife]

As of right now, my server will not send any emails. They all seem to get stuck in the queue. Now, I do have my domain names routed through cloud flare. However, on my previous box running Cpanel, this was not an issue.

The only way email sent works correctly, is if I connect via smtp.gmail.com with my credentials.

On a side note, I noticed my box which is only a month old, for at least a few days, was appearing to be a open relay for emails. In fact, so many, that the cpu usage was starting to spike. I stopped postfix and the issue went away. After making a few changes, like turning on auth for smtp, and turning back on postfix, it seems like they're not connecting anymore.

So, first, is there any extra steps I need to perform to get smtp emails working?

Secondly, the issue with spammers getting in my box, are there any extra steps I can take to make sure this will not happen? Is there a check list of Best Practices for locking down your server?

Thanks,

James

 

[whnunlife]

Okay, quick update. It turns out that the emails being sent to any google hosted email were being denied because of:

Oct 16 13:56:17 u16490957 postfix/smtp[21183]: C38B1489B: host gmail-smtp-in.l.google.com[74.125.142.27] said: 421-4.7.0 [x.x.x.x] Our system has detected an unusual rate of 421-4.7.0 unsolicited mail originating from your IP address. To protect our 421-4.7.0 users from spam, mail sent from your IP address has been temporarily 421-4.7.0 blocked. Please visit http://www.google.com/mail/help/bulk_mail.html 421 4.7.0 to review our Bulk Email Senders Guidelines. e7si13093798icu.19 (in reply to end of DATA command)

Now that I think I stopped the mass spam, I came across another issue. When trying to send via smtp, no matter what I enter for the password, the email is always sent. Seems that the auth is not working when sent via localhost. Again, this is with CentOS running Panel 11.

I was running postfix and switched over to qmail to see if there were any changes and still, emails are sent via smtp when auth is required in the panel, but an incorrect password is supplied. So odd...