A few days ago I hosted a server that I had previously played at with
some friends months ago.

After starting it up again I had a buddy try to connect, but he only
succeeded in getting timed-out. It seems that no one outside the LAN can
connect to it now.

Two differences I noticed:

The ping forever holds at zero.

and

The port number is around 58900 even though the Server Port number
is set to 12300 like most of the other servers I see on the master.

Please let me know how to correct this problem.

GA BlueBlender

Sounds like a router issue. Are you forwarding ports correctly? Is there any router or system firewall?