For some reason I can ping all servers in my network except for the mail server and the mail server can ping all servers except the windows server 2008 R2. The firewall has been disabled and still it doesn't respond. The weird part is that every once in a while it will all of a sudden start allowing pings and then just as suddenly stop allowing pings. I've made sure there's no type-o's in the ip address or subnet mask or gateway. Any other ideas?
Perhaps test with PathPing to help determine where along the path the signal is dying?
Note: You have to run PathPing in an elevated command prompt on Windows 2008 to get results.
if, while pinging, you do arp -a on the client sending ping, do you see the mac address resolved ?
Can you RDP to the server ? I mean, it's working as a mail server anyway ?
How did you disable the firewall ? could you use this command to disable it ?