[SOLVED] Does Xfinity support NAT(port forwarding) and how to set it up?

zzzhhh

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May 13, 2018
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Never got through any human Xfinity customer support, so have to ask here ...

I'm trying to set up NAT (port forwarding) so that I can access my home computer from outside. This was once a very easy job when I used AT&T internet service, but after I moved to a city that uses Xfinity, I don't know how to bring my past convenience back. There are two obstacles in front of me: 1) Is the IP static? The IP Chicken tells me that the IP of my home PC is 68.59.125.xxx. Is this a public IP? Seems not an internal IP to the best of my knowledge and it seems not changing. 2) How to set up NAT (port forwarding)? I did not find anywhere in the network management webpage (something like http://10.10.10.0, I don't remember that) to do that. I'm going to return the rented cable modem back to Xfinity and buy a new one of my own. Will the address and contents of the network management webpage change? Is there any chance that the new cable modem I'm going to buy (I'm interested in MOTOROLA ARRIS SBG6580) is able to provide settings of NAT(port forwarding)? Please let me know if you need more information to answer the above questions. Thank you.
 
Solution
If I can get through a human technical support who knows tech.
So the answer to "is the web server of the gateway address maintained by the particular device" is yes? That is, there is a flash memory in the device that stores web server code for network administration and my username/password, though XFinity has access to change it remotely?
So, 68.59.125.xxx is a public IP, but dynamic, though it remains static for a long time (like internal IP assigned by DHCP to my home PC)? If yes, I can use 68.59.125.xxx:nat_portnum to communicate with my home PC from outside, where nat_portnum is what I set in NAT settings for my PC within my home LAN, right?
This is really, really basic stuff. Just tell them you need access to the web...
ip chicken--now that's a name I've not heard in a long time...

Even with the xfinity stock equipment, you should be able to set up port forwarding and even dmz if you need it. You simply go to the address of the default gateway of your system's ip address. You don't need to get your own modem/router unless you want them. Keep in mind that any combo unit will work just like the provided one, so better to get a separate modem and router if you plan to get your own equipment.
 

zzzhhh

Honorable
May 13, 2018
86
3
10,535
ip chicken--now that's a name I've not heard in a long time...

Even with the xfinity stock equipment, you should be able to set up port forwarding and even dmz if you need it. You simply go to the address of the default gateway of your system's ip address. You don't need to get your own modem/router unless you want them. Keep in mind that any combo unit will work just like the provided one, so better to get a separate modem and router if you plan to get your own equipment.

But I can't. First I can't login using the username and password on the label of the leased gateway. Second, during my last successful login, I cannot find where to set up NAT (then I'm not able to login. Don't know what happened). So, if I buy a new cable modem (I have to because I am charged $14 per month for the leased modem), will the username and password be changed to the new one, and will the contents of the network administration webpage be changed so that I can find out the place to set up port forwarding more easily (to be more technical, is the web server of the gateway address maintained by the particular device)? Also, in Xfinity, is the IP I got from IP Chicken (68.59.125.xxx) a static public one (i.e., I can use it for port forwarding from outside), or do I have to buy one from Xfinity (I didn't have to when I was with AT&T)?
 
But I can't. First I can't login using the username and password on the label of the leased gateway. Second, during my last successful login, I cannot find where to set up NAT (then I'm not able to login. Don't know what happened). So, if I buy a new cable modem (I have to because I am charged $14 per month for the leased modem), will the username and password be changed to the new one, and will the contents of the network administration webpage be changed so that I can find out the place to set up port forwarding more easily (to be more technical, is the web server of the gateway address maintained by the particular device)? Also, in Xfinity, is the IP I got from IP Chicken (68.59.125.xxx) a static public one (i.e., I can use it for port forwarding from outside), or do I have to buy one from Xfinity (I didn't have to when I was with AT&T)?
Then you're doing something wrong and support should help you get in. A compatible gateway will look the exact same (I got one of these at first when trying to get around a dmz problem). Either leased or your own gateway, you should have access to the device for the nat access; however, they can reset it since they have full access to the unit. Any IP from almost any consumer isp is a dynamic IP; however, in my experience an IP only changes whenever the modem is disconnected for more than a day or when there is a infrastructure change at the isp. So you will be able to use this IP address until it changes. In my experience with the 3x cable provider accounts I have with 3x different companies, it will change every 2 years, if not sooner.
 

zzzhhh

Honorable
May 13, 2018
86
3
10,535
Then you're doing something wrong and support should help you get in. A compatible gateway will look the exact same (I got one of these at first when trying to get around a dmz problem). Either leased or your own gateway, you should have access to the device for the nat access; however, they can reset it since they have full access to the unit. Any IP from almost any consumer isp is a dynamic IP; however, in my experience an IP only changes whenever the modem is disconnected for more than a day or when there is a infrastructure change at the isp. So you will be able to use this IP address until it changes. In my experience with the 3x cable provider accounts I have with 3x different companies, it will change every 2 years, if not sooner.
If I can get through a human technical support who knows tech.
So the answer to "is the web server of the gateway address maintained by the particular device" is yes? That is, there is a flash memory in the device that stores web server code for network administration and my username/password, though XFinity has access to change it remotely?
So, 68.59.125.xxx is a public IP, but dynamic, though it remains static for a long time (like internal IP assigned by DHCP to my home PC)? If yes, I can use 68.59.125.xxx:nat_portnum to communicate with my home PC from outside, where nat_portnum is what I set in NAT settings for my PC within my home LAN, right?
 
If I can get through a human technical support who knows tech.
So the answer to "is the web server of the gateway address maintained by the particular device" is yes? That is, there is a flash memory in the device that stores web server code for network administration and my username/password, though XFinity has access to change it remotely?
So, 68.59.125.xxx is a public IP, but dynamic, though it remains static for a long time (like internal IP assigned by DHCP to my home PC)? If yes, I can use 68.59.125.xxx:nat_portnum to communicate with my home PC from outside, where nat_portnum is what I set in NAT settings for my PC within my home LAN, right?
This is really, really basic stuff. Just tell them you need access to the web interface of the router to change the wifi password--should be that simple.

Xfinity can't change your username/pw, but they can reset the device which can reset any passwords.

Yep, you can use the dhcp public IP like a static and it will simply not work when the IP changes because then you are trying to access something other than your home. I would caution you about opening ports to the Internet though--I have enterprise equipment and I see the packets of the port scanners and baddies out there and they are A LOT. Someone can find and hack your system within a week of going live (if even that long).
 
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