Resource to troubleshoot SMTP setup

Answered

durangod

• May 10, 2025 05:09
• Edited

Hi, is there a cPanel provided resource to troubleshoot SMTP email.   I need to run through the entire server SMTP setup again top to bottom and make sure everything in WHM is set correctly.   

I have been having alot of issues with timed out connections, cant find server, cant connect to server and could not get mail server response.   Does cpanel doc have a "current" rundown of this or is there a preferred resource i can walk through. 

I know i have a similar post back in 2014 but that is almost 10 years old and im sure alot has changed since then.  

I am on a VPS

I am the only user on this server

I am running WHM 126.0.16  and AlmaLinux v8.10.0 STANDARD kvm 

I have also restricted access to the server to my local dedicated ip address from my internet provider, this way noone can log in unless they are using that dedicated ip address.  

Thanks  :)

 

• 

  durangod

  • May 10, 2025 06:52

  i found the problem,  seems my country ip has been banned somehow.  If i did do it i dont remember doing it and it seems its been that way for awhile now.  

  This resource helped alot 

  https://docs.cpanel.net/knowledge-base/cpanel-product/the-cpanel-log-files/

  in the exim mainlog i found this (actually a bunch of them)

  2025-05-10 06:40:08 cwd=/etc/csf 2 args: /usr/sbin/exim -bpc
  2025-05-10 06:41:05 SMTP connection from [MY_CPANEL_IP_ADDRESS]:43490 (TCP/IP connection count = 1)
  2025-05-10 06:41:05 H=[MY_CPANEL_IP_ADDRESS]:43490 dropped by 'connect' ACL: Country is banned

  So it appears (i think) that its telling me that somewhere in csf i have blocked my country so ill have to go find out where.   I have already removed the country block country codes but ill have to check the rules to see if its listed in there.  

  Anyway that is the issue why my SMTP is not working.  :)  

   

   

   

  0
• 

  quietFinn

  • May 10, 2025 12:35

  Blocking IPs by country is not 100% accurate, so if you are blocking any country it might be blocking IPs from your country also.

   

  1
• 

  durangod

  • May 16, 2025 16:19

  update. 

  So as it turns out the country block nor the host access control nor csf port blocks are the issue.  Still cannot connect to smtp server.   Working with my VPS server host we have discovered that the issue is deep in the server somewhere either with exim or socket issue. 

  so they want to do this:

  > We’d like to check if Exim is running correctly and listening on SMTP ports from within the server itself.
  > We’ll also need to check test sending using the telnet or openssl command directly from the server to confirm internal socket connections work.

   

  Question - is what they want to do easy enough that i can do it myself ?   I want to learn how to do this.  If so can you provide some resource links. 

  Thanks :)

  0
• 

  durangod

  • May 16, 2025 23:28
  • Edited

  Hi, as to the SMTP issue.  Awhile back i was trying to learn how to set up a email filters on the VPS and i created one but left it blank as i meant to get back to it later.   It appears that i  had 2 issues with the SMTP. 

  1. I had a disabled custom email filter that had a bad command in it and it was blocking email because even with it being turned off, disabled it still blocked email.

  2. They had to restart lfd csf because the firewall was not showing correctly (whatever that means)   not sure what happened with that part because every time i make a change to the firewall i restart it and also i had just done a system reboot before they went in to look at it.  But anyway that is what i was told.  

  So just be aware that disabled email filters can block email if there is an error in them.   Cost me $15 but worth every penny, the issue has been resolved. 

  1

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