Windows Command to check if a remote server port is opened?

Question

I have two Windows Servers.. Server A and Server B. There is a service configured on Server A to listen on port P. Is there a way to check if the port is opened in Windows Server B irrespective of service running or not. One way is telnet ..but this would work only if the service is running and listening on Port. But, is there a way to find if the port is opened irrespective of the service state? Linux has an "nc" command to achieve the same. Do we have something similar in Windows?

Thanks.!

Solution

You can use netstat.exe to query for open ports.

netstat.exe:

C:\Users\user>netstat.exe /?

Displays protocol statistics and current TCP/IP network connections.

NETSTAT [-a] [-b] [-e] [-f] [-n] [-o] [-p proto] [-r] [-s] [-x] [-t] [interval]

  -a            Displays all connections and listening ports.

example netstat -a:

C:\Users\user>netstat -a

Active Connections

  Proto  Local Address          Foreign Address        State
  TCP    0.0.0.0:135            10.10.11.20:0           LISTENING
  TCP    0.0.0.0:445            10.10.11.20:0           LISTENING
  TCP    0.0.0.0:1433           10.10.11.20:0           LISTENING
  TCP    0.0.0.0:1801           10.10.11.20:0           LISTENING
  TCP    0.0.0.0:2103           10.10.11.20:0           LISTENING

To do a remote netstat.exe you can use psexec tool (free avaiable from here)

example:

C:\Users\user>psexec \\10.10.21.145 netstat -a

PsExec v2.11 - Execute processes remotely
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Active Connections

  Proto  Local Address          Foreign Address        State
  TCP    0.0.0.0:135            10.10.21.145:0         LISTENING
  TCP    0.0.0.0:445            10.10.21.145:0         LISTENING
  TCP    0.0.0.0:2701           10.10.21.145:0         LISTENING
  TCP    0.0.0.0:3389           10.10.21.145:0         LISTENING

Comments

[Jonathon Reinhart]

Install cygwin and use nc.