Blocked Internet Access Question

[mark4man]

People,

Every so often, my Firewall (Norton Personal Firewall) pops up an Internet Access Control window during web surfing that advises I block a high risk remote system which is attempting to access my machine.

I always opt for the block; never giving it much thought...& then continue on.

Today, out of curiosity, I went to Internet Access Control in NPF to see what these remote systems were.

They were various Inbound TCP, UDP, IMCP & NetBIOS Services...utilizing any number of different ports.

What are these services; & how does this all work?

Thanks very much,

mark4man

[Budfred]

If you blocked them and it didn't cause a problem, it doesn't really matter what they are.... Probably some of them are legit and many of them are hackers looking for vulnerable systems. If you didn't block them, you might be dealing with trojans, hijackers and such....

[Steve]

What are these services; & how does this all work?

Here are some links that explain things far better than I ever could...

TCP (http://www.webopedia.com/TERM/T/TCP.html)

UDP (http://www.webopedia.com/TERM/U/User_Datagram_Protocol.html)

NetBIOS (http://www.webopedia.com/TERM/N/NetBIOS.html)

ICMP (http://www.webopedia.com/TERM/I/ICMP.html)

Hope that helps a little...:)

[mark4man]

Budfred & Steve,

Thanks very much,

mark4man