i have customer running Cisco IPSEC Remote VPN to access their file server.
basically, the file server is behind second tier of their corp firewall. 1st tier firewall is belongs to their corp IT and maintenance by them.
my customer owned the 2nd tier firewall, and we just basically permit the VPN subnet to our server LAN. this setup has been works for 3 years and out of the sudden, the VPN users no longer able to access the file server.
if I run telnet to server's port 445, it can go through. only if I run \\ip address of the server, it will prompt error saying the network name no longer available. I have tried by name and IP also returned with same result.
I ran wireshark at the file server it self, and did a telnet from vpn client, I can see there is traffic come in from the client IP with port 445.
Much appreciate any help....