Problems after upgrade

Hi,

I upgraded from 3.43 to 3.54 yesterday, I thought it was meant to happen automatically but when I noticed I was running an old version I re-ran the install script. There seemed to be some errors about being unable to connect to the mirror so I needed to run the install about 12 times before it was successful. After it finished I ran yum update I get an error about 'Connection refused' tying other mirror...

I am now getting some strange errors being reported by clients saying that their mail isn't working.

I am wondering if it is a networking issue.

I have had some DNS issues in the past but I have still got a different server basically running as a DNS host. Which I need to fix at some stage but currently it is working ok I think

Mitch