Originally Posted by chort
It sounds like your ISP is blocking port 25/tcp both inbound and outbound on their network, except to/from their own mail server. You could send outbound mail to other domains by setting up sendmail to authenticate to your ISP's mailserver and use it as a smarthost, but that's not going to help inbound mail reach you.
With the work laptop I RD'd to our work server and ran ping/telnet from there.
The responses I got were:
telnet dns.nmeinc.net -> could not connect to the host on port 23. Connect failed
telnet dns.nmeinc.net 25 -> could not connect to the host on port 25. Connect failed
telnet mail.nmeinc.net 25 -> could not connect to the host on port 25. Connect failed
ping on both machines works fine. mail.nmeinc.net = dns.nmeinc.net
perhaps the telnet port is also being blocked?