My IP can't be pinged/is unreachable...

[ArcticZero]

Hello. I'm running (or at least trying to) a Counter-Strike: Source Dedicated Server on one of my PCs (Windows Vista Ultimate x64). I've also been running an Apache Web Server (remotely accessible) for my Web Development portfolio for a long time now with no issues. I'm on a Zyxel P-600 Series modem/router. As for the dynamic IP issues, I use http://www.no-ip.com for my Dynamic DNS.

My problem is this:

Sometimes, people can connect to my server, and sometimes they just can't. Sometimes still, people can only connect if I give them the actual IP address, and not the no-ip.com address. Upon doing some research, I noticed that it usually happens after a while of the server being on with someone in it. It's running on port 27015, btw. The port has been forwarded on the modem and I'm not running a software firewall apart from the one built into Windows Vista, which already has 27015 open. I also noticed that when people can't connect to my server anymore, it's because they can't even ping my IP address. It becomes unreachable, and they time out. I've tried http://www.whatismyip.com to get my external IP, and having them ping it. Nada.

I've tried restarting the modem, and still nothing. Thing is, even while all this is happening, my connection is fine from my end. Why is my IP sometimes unreachable? Also I noticed that when I restarted my modem, I got the same IP address even when I'm supposed to be on a dynamic IP range. But I dunno if that matters, as I don't even know when dynamic IPs are supposed to change for end users.

The main point is that most of the time, my IP/DDNS can't even be pinged. I'm starting to lose hope here... Hope you guys can help me out! Thanks!

[DjDigiD]

I'll take a shot in the dark and say your ISP is cutting you off, sounds like your running this server from a HOME connection. Check to make sure you are alowed to run a dedicated server off your connection, most ISP's dont let you. They could verywell be blocking all these connections to your IP, if and when they do it is tempoary then ppl can connect again?

[ArcticZero]

Yeah, if you can ping the server, all is good. Guys here can connect and get about 20-30 latency. I've been running an Apache Web Server for the longest time now with no issues, so I don't get why all of a sudden, problems like this start occurring. Btw, when the symptoms started to occur, people couldn't even access my web server anymore.

Thanks for the reply!