Port Forwarding with Xfinity Modem

[Shadowraix]

Alright so I have a router up in my room that I am connected to ethernet to because I can only use ethernet at the moment. I have an xfinity modem with wifi capabilities that has a router connected to it via ethernet then my router being used as a wireless repeater. Port forwarding via the router I'm on has no effect. So I figured that I needed to port forward on the xfinity modem. I don't know what IP to put though. I can't put the regular 192.168.1.xxx IP because I get a "different subnet with dut lan ip" error. The xfinity modem seems to have a 10.0.0.x setup. Any help?

 

[inerax]

Ignore me... I dident read your post....

Any reason you are not plugged direct into the comcast modem?

Hooking router to router can cause some problems.

It would be better if you got a switch for this. That way the router will still assign you a 10.x.x.x IP address.



You can try to login to your router (the 2nd one) and see what IP it has. It should be getting a 10.x.x.x IP address from the Comcast modem. You can use that IP to forward inside the comcast settings.

 

[Shadowraix]

Ignore me... I dident read your post....

Any reason you are not plugged direct into the comcast modem?

Hooking router to router can cause some problems.

It would be better if you got a switch for this. That way the router will still assign you a 10.x.x.x IP address.



You can try to login to your router (the 2nd one) and see what IP it has. It should be getting a 10.x.x.x IP address from the Comcast modem. You can use that IP to forward inside the comcast settings.

Wifi is not an option. I must use this method so that I can achieve some form of wired connection with a device that requires no coax cable. Cable in my room is messed up and no wifi card in my PC so I can only do wifi. Everything was fine and worked perfectly until the new modem came into the picture.

 

[inerax]

But you are running a 2nd router that is not the comcast router?

Why can you not plug ethernet direct into the Comcast modem?

I'm wondering why a 2nd router is in the mix.

The Comcast modem has 4 ports in the back right?

 

[Shadowraix]

But you are running a 2nd router that is not the comcast router?

Why can you not plug ethernet direct into the Comcast modem?

I'm wondering why a 2nd router is in the mix.

The Comcast modem has 4 ports in the back right?

My computer is setup too far away from the comcast modem. I have a 3 story house with the modem and primary router on the bottom floor with me and the repeater router on the 3rd floor. I tried to setup the stuff in my room, but like I said the cable chord is messed up. So my setup is 1 router connected to modem via ethernet and one in my room that serves as a repeater. The repeater being necessary as I have no wifi capabilities. Both routers are netgear.

 

[inerax]

Ahhh now i got it... I thought you were hard wiring the router to the modem. Guess I cannot read today... or understand.

Login to the router that is acting as a repeater. On the info page you will find a 10.x.x.x IP address. This is the IP address being assigned by the Comcast modem.

You can port forward that IP inside the Comcast modem.

 

[Bimmer_Nut]

Alright so I have a router up in my room that I am connected to ethernet to because I can only use ethernet at the moment. I have an xfinity modem with wifi capabilities that has a router connected to it via ethernet then my router being used as a wireless repeater. Port forwarding via the router I'm on has no effect. So I figured that I needed to port forward on the xfinity modem. I don't know what IP to put though. I can't put the regular 192.168.1.xxx IP because I get a "different subnet with dut lan ip" error. The xfinity modem seems to have a 10.0.0.x setup. Any help?

Okay i realize that this is an old thread. 1) purchase a Linksys Powerline Ethernet adapter. Install on adapter by your xfinity router and plug it directly into a wall outlet, NOT a power strip.
Install the second adapter by your computer that needs LAN access.
Use this method if you don't have ethernet connections to another floor or room and wireless won't function because of the distance.

2) adding a secondary router behind an xfinity router
If all you want to do is be able to have internet or wireless from your secondary router you need to assign a static IP to the WAN of your secondary router.
Assisgn a static WAN ip to your secondary router, example: 10.1.10.254 with a subnet of 255.255.255.0 gateway: 10.1.10.1 and dns 10.1.10.1
Then on your xfinity router set what ever static ip you assigned to your secondary router as a valid IP.
You must assign an ip, or you can tell your secondary router that you want dhcp on the WAN side. I don't recommend this method of you need to forward ports to your devices, in this case only use static.
Set up what ports you need forwarded to what ever static ip you have assigned to your computer. Yes I said Static, with port forwarding never use dhcp on your computers or laptops.
Then on your xfinity router assign the 10.1.10.254 as an allowed address.
Then forward any ports that need outside access in to the 10.1.10.254 IP.
Pretty simple, that is unless you are using a P.O.S. Netgear router which really sucks, I recommend Cisco/Linksys or Asus.

The reason why I never use an xfinity router for controlling my network is there is no way to assign static ip's to mac addresses within a dhcp pool. I hate dhcp, I've always felt dhcp is for lazy I.T. people or dummies.

I also recommend subscribing to a dns service like dyndns.org, makes it easy to create an alias instead of remembering a ton of WAN IP Addresses.