SOLVED SMTP Restrictions Disabled but Still Blocked

pixelaté

Member
May 21, 2008
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Hi, I've disabled SMTP restrictions so an account can send email via a third-party SMTP server (Office 365). The issue is, for end-user accounts, port 587 is still blocked despite disabling SMTP restrictions. For root however, it's not blocked - as if SMTP restrictions were still enabled.

I've rebooted the server just to be sure to no effect. Any ideas?

Thanks,

Ian
 

cPanelMichael

Technical Support Community Manager
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Apr 11, 2011
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Hello Ian,

Do you happen to use the CSF firewall application? If so, check the CSF configuration to make sure it's not blocking the connection attempt:

CSF > Firewall Configuration > SMTP Settings > SMTP_BLOCK

Block outgoing SMTP except for root, exim and mailman (forces scripts/users
to use the exim/sendmail binary instead of sockets access). This replaces the
protection as WHM > Tweak Settings > SMTP Tweaks

This option uses the iptables ipt_owner/xt_owner module and must be loaded
for it to work. It may not be available on some VPS platforms

Note: Run /etc/csf/csftest.pl to check whether this option will function on
this server
Thank you.
 

pixelaté

Member
May 21, 2008
7
1
53
Hi @cPanelMichael you were right. I wasn't aware that CSF had their own version of SMTP Restrictions. I had only looked in the open and closed ports in CSF.

For anyone else who has a similar problem, it the section of CSF Configuration titled SMTP Settings and the setting is SMTP_BLOCK. In my case, I added the user to SMTP_ALLOWUSER

Thanks for your help!

Ian
 
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cPanelMichael

Technical Support Community Manager
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Apr 11, 2011
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Hello Vince,

To solve the issue, the individual cPanel username was added to the SMTP_ALLOWUSER option under the SMTP Settings section in WHM >> CSF >> Firewall Configuration. Keep in mind that CSF is a third-party application, so it's not something that's configured or setup by default as part of a standard cPanel & WHM installation.

Thank you.