Strange networking problem on higher port numbers

[kangarolf]

Hi all,

We have a remote server running msSQL on port 1433. We have somehoe
developed a fault on our intranet and no machines can connect to the
msSQL server on port 1433, though the server is running fine and
serving locally based websites and I can also connect from outside of
the intranet.

I investigated further using a port sniffer on the server and no
connection request is received on port 1433. In fact no connection
request is received on any port above 1250..!!?? FTP still works as do
connection request on any port below 1250.

I have checked all the DNS settings and everything seems to be in
order. All firewalls were disabled with the same results. I can
tracert the route to the server with no issues.

Has anyone any idea what else I can try or what on earth might be
causing this strange behaviour..?

Thank you
Rolf

 

[Arijit Bhattacharyya]

does the server have a AV software which has any IPS , this might prevent
connections to non standard ports. also check if you have turned on the
windows fw on network interface of the server.

i assume the server on the network is under the same subnet the workstations
belong to , there is no firewall in between or no seperate vlan.