Why can't I connect on port 445?

Question

I need to collect baseline performance data on a SQL Server running on Windows Server 2008 R2. When I open perfmon on my computer running Windows 7 and try to add counters from the remote server, I receive an error stating "Unable to connect to the machine."

I can ping the server, and I can connect using Remote Desktop.

In addition to the perfmon issue, I cannot browse shares (e.g. \uncpath\c$), connect to the remote registry, or connect to port 445 over telnet.

I'm on the same subnet as the server, and the Windows Firewall is turned off on both the server and my computer.

Solution

I know this is old but might as well add some answer to this question for future use...

Make sure you can connect

telnet thehostname 445

Or on linux

 nc -v -w3 thehostname 445
 Connection to test-ws1 445 port [tcp/microsoft-ds] succeeded!

Make sure something is listening

C:\Users\Administrator>netstat -ao | find "445"
  TCP    0.0.0.0:445            thehostname:0             LISTENING       4
  TCP    [::]:445               thehostname:0             LISTENING       4

Make sure file and printer sharing is enabled on that interface

The last one got me

Comments

[voretaq7]

It may seem obvious, but have you verified there's actually something listening on the target machine? (do connections work from localhost? Does netstat show listeners where you expect them?) -- Assuming everything else you're reporting is accurate the only reason I can think of that you can't connect to this host is that it's not listening...

[Tim]

Doesn't perfmon use RPC or ADMIN$ shares to poll it's data? Is RPC blocked somehow?

[Rob D.]

@RemusRusanu There are no dynamic or static ipsec policies configured on the server (checked using netsh ipsec dynamic show all and netsh ipsec static show all).

[Rob D.]

I just had an opportunity to restart the server and that has corrected the problem for now.

[Rob D.]

Restarting the server resolved the error, and the problem hasn't recurred since. I guess it will remain a mystery.

[Jerad Rose]

but if you can't telnet then the 'last one' is irrelevant right?

[KCD]

If you cannot connect you should resolve that first. There could be a number of things not working but not being able to reach the desired port is a reliable test

[Jerad Rose]

Every time I tried to turn this option on it just turned itself off and I don't want to risk losing connectivity so I gave up. This is on a godaddy server that's being retired. At home I have uverse which apparently blocks it anyway.