Issue Outbound Mail Resolving to Local IP

[Dome1990]

Receiving Mail to the Plesk server on multiple domains seems to be working fine. but when sending outbound mail to any external domain it seems to be always resolving to a local IP address see below


----------DNS on CentOs ---------------
search domainname.local domainname.com
nameserver 10.11.10.1
nameserver 10.11.10.18



---------------------Mail Non Delivery Report------------
Reporting-MTA: dns; plesk.external.domain
X-Postfix-Queue-ID: C4650219631B
X-Postfix-Sender: rfc822; mail@external.domain
Arrival-Date: Thu, 22 Oct 2020 23:24:09 +0100 (BST)

Final-Recipient: rfc822; emailaddress@googlemail.com
Original-Recipient: rfc822;emailaddress@googlemail.com
Action: failed
Status: 4.4.1
Diagnostic-Code: X-Postfix; connect to googlemail.com[10.10.10.11]:25:
Connection timed out
---------------------Mail Non Delivery Report------------


That address is not even part of the subnet the server is on. so I'm not sure where it's getting it from On another note I have enabled debug logging on the firewall on the ruleset that applies to Plesk. there are no blocks being reported by the ASA.

If anyone has an idea where that internal IP could be coming from I belive that is the route cause of the issue but I can't seem to find it anywhere.

Thanks

PS be gentle it's my first post


Plesk Version:

IP address
10.11.10.15 (External IP Obfuscated)
OS
CentOS Linux 7.9.2009 (Core)
Product
Plesk Obsidian
Version 18.0.30 Update #3, last updated on Nov 12, 2020 03:20 AM

 

[Bitpalast]

Have you considered using public DNS in your /etc/resolv.conf file, such as Google's 8.8.8.8 and 8.8.4.4?

 

[Dome1990]

Have you considered using public DNS in your /etc/resolv.conf file, such as Google's 8.8.8.8 and 8.8.4.4

Thanks for the reply. I have tried changing them to 1.1.1.1 and 8.8.8.8, sent another mail-out which has still not been received. ill await the delivery failure report and see what it's saying.

Cheers Peter