Server not responding...cant find an answer

[Sorrow]

Okay... I been following tutorials from all different places to make sure I was doing this correctly and I believe I followed the basic instructions precise... Heres what happens I start up my server everything looks to be running smoothly and when I go to join it through Counter-Strike Source it says "Server Not Responding". I also had my friends try and join with the same problem except they could join but it would kick them saying something wrong with server connection or somewhat. Now I have ran a server before a while ago with success but for some reason I must be doing something wrong... I made sure I forwarded ports on my router and got the external ip... I updated how I believe I should...

Any help at all would be appreciated.
Thanks.

[Spartanfrog]

Try to DMZ your server.

[Sorrow]

I'm sorry but what is "DMZ"?

[HBS|Ryan]

http://www.boutell.com/newfaq/creating/dmz.html