# Check if port is open from CMD



## DexterDave (May 10, 2011)

Hi All

I would like to know if there is a way I can test if a specific port is open on an IP address and if my PC can connect to that port?
How do you do this from Command Prompt? 'telnet iport' does not seem to work since it just says 'telnet' is not recognized as an internal or external command. 

I do not want to use a website to do this, since they will test if they can make a connection from their servers to the ip port in question, not if the port between my IP address and the ip in question is open.

I know about NMAP and Netcat, but don't know how that works. 

What is the best way to do this in windows?

Thanks


----------



## Squashman (Apr 4, 2003)

Do you have to do this from the cmd shell?


----------



## lunarlander (Sep 22, 2007)

Windows 7 does not have telnet, as you probably figured out by now. You'll have to use Putty. (free)

A port that is open is connectable from any where. It does not mean there is some magical pathway from your PC to the other PC. If you use a website to do this, it may fail because you have a NAT router, and I am guessing that both PC's are behind a router.


----------



## Squashman (Apr 4, 2003)

lunarlander said:


> A port that is open is connectable from any where.


Technically not true. We have plenty of clients where they setup access control lists to only accept coonections for certain protocols only from specific IP addresses.


----------



## lunarlander (Sep 22, 2007)

Squashman
Yeah you're right. Forgot about that.


----------



## DexterDave (May 10, 2011)

ok cool. so it is putty then? also, why would NATting make this port scanning fail?


----------



## Squashman (Apr 4, 2003)

lunarlander said:


> Windows 7 does not have telnet, as you probably figured out by now. You'll have to use Putty. (free)


Start
Control Panel
Programs And Features
Turn Windows features on or off
Check Telnet Client
Hit OK


----------



## DexterDave (May 10, 2011)

@Squashman - Telnet has two options in Windows Features: Telnet Client, and Telnet server. For my purposes, do I need the Telnet Server? Thanks for your answer


----------



## lunarlander (Sep 22, 2007)

> Turn Windows features on or off


So thats where they hid it. And I thought they finally did away with it since XP.


----------

