I am having problems setting up a new Comcast business cable modem gateway and thought someone here might be able to help offer some insight.
First let me start of by saying that everything was setup and working fine, until about 2 weeks ago, I woke up and realized that my Comcast cable modem had been reset and was no longer working. I called Comcast and they confirmed that there was a firmware upgrade and it “did not work” and so they could not even log into the cable modem. So they came out to replace it.
We have 1 static IP address which is used to host our website, and with the previous cable modem it was pretty easy to setup and it was working fine for about 2 years.
For my setup I have it pretty simple:
Comcast Cable Modem
External IP: 173.160.46.xx
Static IP: 173.160.46.yy
Gateway IP Address: 10.1.10.1
Web Server with 2 NICs:
Internal IP Address: 10.1.10.181
External IP 173.160.46.yy (same as the static IP address above)
So far so go, and pretty simple. With the previous cable modem, to get everything working, I just powered on the cable modem, started up the web server, and everything worked fine. Web site traffic coming in on the 173.160.46.yy address went to the web server and all was fine.
Enter the new cable modem.
Initially, we had the same setup, and everything worked fine, but only for a limited time. After some time (no pattern found with how long things worked) but after a while the traffic to the web server would not go through. The web site appeared offline.
After scrambling, I reset the cable modem, and connection was restored. But only again for a limited time. I could not find any pattern or reason why the traffic would stop to the web server. It seemed as if the Comcast cable modem could not find the 173.160.46.yy static IP address of the web server.
I then tried setting up a 1-1 NAT telling the Cable modem to direct any 173.160.46.yy traffic to the internet NIC address of the webserver (10.1.10.181). This now creates a stable enough environment that we don’t drop traffic to the web server.
I’m still not sure of the reason for this, but I guess I have to live with it for now.
My problem/question now is for any computer on the internal LAN, if we try to get to our websites using a browser (ie: www.mycompany.com) we end up at the login prompt of the Comcast cable modem! (basically the same as going to 10.1.10.1). So to get around this now, I have to update the host file on each machine, so that the domain name is mapped to the internal address of the web server (10.10.181).
So my question is how can I setup the Comcast cable modem/router to route any internal traffic that is trying to get to the web server (at the static IP address of 173.160.46.yy over to the actual web server machine using the internet IP address 10.1.10.181?
When I called Comcast, and reviewed the situation, they said since I have the 1-1NAT setup, I can’t route internally now to my web server, and there is no way to setup a static route to it.
Any help would be appreciated,