[CentOS] New mail server slow connecting to web server

Fri May 25 16:13:44 UTC 2018
Gordon Messmer <gordon.messmer at gmail.com>

On 05/24/2018 09:10 PM, Gary Stainburn wrote:
> name resolution isn't the problem as I can nslookup both ways without
> problems

Can you provide more detail here regarding what tests you performed?  
Long delays are usually a timeout on a reverse DNS lookup (that is, a 
PTR lookup) on the connecting IP address.

Connect to the server, and get the address that the server sees as its 
peer either from the log or using "ss -o state established -t".  Use 
"time host $ip" to test the reverse lookup.  Send the output to the list.