I wonder if you might have an answer for me on this question.
I can ping the IP address of our mail server from my laptop no problems. However I can't ping our mail server IP address from our server which is in a data centre. This is strange because I can ping other IP's from that server that is in the datacentre, I can also ping domain names like www.google.com
Any ideas on what the problem might be? The firewall has ports 25 and 110 open. The mail server is outside the datacentre too.