Ports open on Windows

I noticed that while trying to assess my system's ports, even on a newly intalled machine, port 137, 138, and 139( [img]images/smiles/icon_sad.gif[/img] ) are always open. What are these ports used for and are they a potential threat. My theory is that it is a possible back door for Gates and his staff. [img]images/smiles/icon_wink.gif[/img]

Oh Master [img]images/smiles/icon_smile.gif[/img]

Those ports you mentioned are used by the TCP/IP protocol for Netbios communications.

Putting it in simple terms, using these ports, windows machines can talk to each other and transfer data.

If your on a network at home and your talking to other machines, you need these ports open. If this is a stand alone pc, you can use a 3rd party firewall program e.g Zonealarm to close them up [img]images/smiles/icon_smile.gif[/img]

Cheers,

[img]images/smiles/icon_cool.gif[/img]

The way to disable the ports is to not enable Client for Microsoft Networks and File and Print sharing. I know on the new XP it comes pre-enabled but if you were to disable it you will notice the ports close.

format c: /q /u

quick fix.

Another solution is to disable Netbios over TCP (2000 and XP only)

Just see for yourself
start-->run-->cmd

Netstat -a

NOTICE the netbios entry

Now open your TCP/IP Properties-->Advanced-->WINS

There disable Netbios over TCP.

Now take a look again with netstat -A


Kind regards,

John Bruijntjes MCSE /CCNA

Message for LXS (see earlier posting).....everyone needs a change to learn so if you are so smart go ahead and answer some questions...answer them wrong and i flame you like hell!!! [img]images/smiles/icon_mad.gif[/img]

[ 23 June 2003: Message edited by: JJB ]

The solution is very easy, just type in services.msc into the command prompt and disable the services you don't want running. There is a port tied to each service.

If you arent familiar with all the services, take a trip to www.blackviper.com and familiarize yourself with each one. You would be surprised at how many you can disable and still maintain functionality. [img]images/smiles/icon_smile.gif[/img]

I usually boot up with only 15 or 16 services at any one time.

Have fun.

[ 08 July 2003: Message edited by: FrameWork ]