Internet security and ports

[marklp77]

Why is opening up ports in addition to port 80 such a bad thing?

Thanks in advance,
Mark

[sharder8]

Different ports are used for different things. If you leave your port 137? or 139? open, that will allow someone else, who finds it open and wants to utilize your computer access to just about anything they want to do to your computer. Some ports are used by games for interactive connection, I believe port 80 is used by ICQ for chat purposes and ICQ also has a built in server.

Remember the "Denial of Service" incidents? That was partially caused by many computers being accessed by the perpetrators who then installed programs that tried to access the site all at the same time causing major overload.

This is also one of the reasons many people have installed personal fire walls in order to prevent both the incursion and also programs from phoning home. My personal favorite is ZoneAlarm. It has stopped many hits trying to get into my computer as well as a few programs that have tried to "phone home".

[marklp77]

Thanks for your response.

I guess I don't understand that when you have port 80 open already, why it makes a difference if you open port 21(ftp).

Thanks,
Mark

[This message has been edited by marklp77 (edited 12-18-2000).]

[netsurfer]

Port 80 is reserved for the http protocol. If you have port 80 open and if your computer is setup to respond to port 80, your computer will be able to act as a webserver. Not necessarily a bad thing if you know what you're doing.

137 and 139 are Netbios related ports. So if you're leaving all your drives mapped (or in NT's case with the $ drives) without passwords, with full read/write capabilities and aren't current with the latest bugfixes in regards to those ports, sure.

[This message has been edited by netsurfer (edited 12-18-2000).]