HT502 DMZ and Port Forwarding

I had my HT502 set up the way VOIPO recommends, Cable Modem -> HT502 -> Linksys Router. The setup works fine for phone/internet. I'm getting ready to install an IP security camera system so I tried a port forwarding/DMZ experiment. I configured a Win 7 PC as a web server and tried unsucessfully to set up the HT502 for port forwarding and then for DMZ and couldn't get either of them to work. Port Forwarding thru the Linksys Router works fine. I ended up putting the router back onto the modem and feeding the HT502 from the router and that configuration works OK but I'd like to know why I can't get Port Forwarding or DMZ to work on the HT502.

I've tried 3 calls to Tech Support and haven't had any success. DMZ should be easiest I would think. I set the DMZ address to the IP address that the HT502 had assigned to the router, 192.168.2.100 and rebooted. Nothing!. I am forwarding port 8080 for my server so it's not a port 80 block problem and again, it works fine without the HT502 in the path.

Any help or suggestions would be appreciated.

Assign a fixed IP on the 502 and then have the router port forward 5004-65000 UDP ports to that IP you created on the 502.

I found this to be safer and it works better than DMZ.

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Originally Posted by oldengineer

I had my HT502 set up the way VOIPO recommends, Cable Modem -> HT502 -> Linksys Router. The setup works fine for phone/internet. I'm getting ready to install an IP security camera system so I tried a port forwarding/DMZ experiment. I configured a Win 7 PC as a web server and tried unsucessfully to set up the HT502 for port forwarding and then for DMZ and couldn't get either of them to work. Port Forwarding thru the Linksys Router works fine. I ended up putting the router back onto the modem and feeding the HT502 from the router and that configuration works OK but I'd like to know why I can't get Port Forwarding or DMZ to work on the HT502.

I've tried 3 calls to Tech Support and haven't had any success. DMZ should be easiest I would think. I set the DMZ address to the IP address that the HT502 had assigned to the router, 192.168.2.100 and rebooted. Nothing!. I am forwarding port 8080 for my server so it's not a port 80 block problem and again, it works fine without the HT502 in the path.

Any help or suggestions would be appreciated.

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Things can get a little complicated with double NAT going on......

If your Linksys router is the only device connected to the LAN (router) port of the HT502, then port forwarding or DMZ within the HT502 doesn't really accomplish anything. Any ports not being utilized by the ATA should be available or passed through to your Linksys router. Placing an Ethernet switch between the HT502 and Linksys router should provide the means for you to configure DMZ or Port Forwarding to each of your devices using the HT502. Try this setup:

Cable Modem -> HT502 -> Ethernet switch -> Connect your Linksys router and IP camera to separate ports on the switch

This will allow the HT502 to assign a private IP to each device from its DHCP pool. Within the HT502, reserve a static IP for each device that you wish to DMZ or Port Forward to, then configure the DMZ or Port Forwarding as needed to each of these reserved static IP's.

It sounds like your somewhat tech savvy with networking, so hopefully you can give it a go. Hope this helps....

Update: After looking at the HT502 manual, it seems the HT502 lacks the ability to reserve IP's from its DHCP pool. The HT502 is not a full fledged router, so it's not surprising that it's missing this feature. At this point, this is likely would I'd do.... Log into the camera's configuration menu and disable DHCP, then assign it a static IP using an IP address that is outside the range of the DHCP pool of the HT502. For example, the DHCP pool of the HT502 is normally 192.168.2.100 to 192.168.2.199. You might assign the static IP of the camera to 192.168.2.200 and use the same subnet mask and gateway IP's. Within the HT502, configure the port forwarding settings using the IP you assigned the camera.

Another thought is that it may not be the port forwarding that is the problem.

Your Linksys may have SIP ALG enabled. Find that in the advanced properties and disable it.