*Sigh* Xfinity Modem/Router

[dewman45]

So, to start off, I originally had an Xfinity Modem/Router, and it was working correctly for awhile. I usually have forwarded ports, and run gaming servers. But one day, my external IP changed to a MAC address, for some odd reason, and no one could connect, including myself. This is why I replaced the original router. Now it came down to my previous router dying, so I ordered a new one through Comcast. They are almost worth it now, with dual band, AC wireless capabilities. But, a familiar problem arises. I go to set up ports for my server, which is relatively easy for an Xfinity Modem/Router, and surprise surprise, no one can connect. I go to check my IP, and I see this strange MAC address as my external IP. This, is my curse from Comcast. Please help lift it upon me, and I would appreciate any help. Thanks!

[jagdtigger]

Does it look like this?

 

If so thats not a MAC address but an IPv6 one. Look around in the settings, i bet that your router has separate pages for IPv4 and IPv6.

[Mikensan]

Use a website that lists both your ipv4 and ipv6 such as http://ip-lookup.net/. A lot of carriers are doing encapsulation and if a site/service accepts ipv6 then that is what gets used.

[dewman45]

I have. I know what an IPV6 looks like, and I can distinguish between and IPV4. But this is like a MAC address, but in a format I have never seen before. This is the address everything is telling me is my external IP:  2601:245:8100:1142:cd1e:70fa:5194:de08

Weird, I know. Still an octet, but I don't what kind of address this is. Same happened with the old comcast router, but it originally worked. This one did it right out of the box. Tech support is out of the question, because last time they suggested replacing the router. They will tell me that they are not qualified to help me with that problem, and even if they were, they are only allowed to help me connect to the internet.

Edit: just checked command prompt, and this is my IPv6/MAC address. I don't wtf is going on with this...

[jagdtigger]

I told you, its IPv6. IPv6 addresses have 8 segments, if a segment or more has only 0 in it it can be omitted and replaced with "::" :

I have a hunch that your router not do NAT on IPv6, ask one of your friends to try a direct connection  with your servers IPv6 address and not the routers.

[Mikensan]

Did you bother going to the site I recommended? If you log in to the modem and look at the WAN dhcp IP address, does it also show the IPv6 address? You could also just go to google.com and write it out as a question and google will return your ip address too but it may return your ipv6.

 

Sites to try:

http://lmgtfy.com/?q=what+is+my+ip+address

http://ip-lookup.net/

http://ipv4.whatismyv6.com/

 

[dewman45]

All of those list different IP's that do not work, or they also show the MAC address. I really don't understand why Comcast does this. I have never seen an IPv6 come up as an external IP address. I checked on the router settings, and the external IPV4 there does not work either. Using an IPV6 to connect to servers will not work either. I am not saying they do not work, without trying it first. Unless Comcast is switching to IPV6 standard for external IPs(which I really doubt) then I am thrown for a loop.

[Donut417]

My friend had issues with port forwarding on his Xfinity Modem/Router. He ended up having to restart the device. This sounds strange. Because you should have both a Ipv4 and IPv6 address. All you can do it restart it and see what happens. 

[jagdtigger]

11 hours ago, dewman45 said:

All of those list different IP's that do not work, or they also show the MAC address. I really don't understand why Comcast does this. I have never seen an IPv6 come up as an external IP address. I checked on the router settings, and the external IPV4 there does not work either. Using an IPV6 to connect to servers will not work either. I am not saying they do not work, without trying it first. Unless Comcast is switching to IPV6 standard for external IPs(which I really doubt) then I am thrown for a loop.

And what if Comcast uses NAT for IPv4 and your servers dont support(or you have to force it with launch options) IPv6? That would explain this weird situation...

[Donut417]

13 hours ago, jagdtigger said:

And what if Comcast uses NAT for IPv4 and your servers dont support(or you have to force it with launch options) IPv6? That would explain this weird situation...

Are you talking about Carrier based NAT. Because Comcast doesnt do that. ATT does but not Comcast. I get both IPv4 and IPv6 Ip addresses, as I understand it your router should do all the rest. 

[dewman45]

Well, I move out after this summer, so I will just have to stick it out and give people the files to run it for me temporarily.

[Donut417]

50 minutes ago, dewman45 said:

Well, I move out after this summer, so I will just have to stick it out and give people the files to run it for me temporarily.

Well I can tell you this. My friend has one of those Comcast modems and In order to get port forwarding to work he had to reboot it. I think there modems might be bugged. 

[dewman45]

Probably being this was the problem that made me get rid of the first one before. The first one originally didn't do this, until one day it did. I guess after that they've done that for some people. If you look it up on google, nothing will come up. Well, maybe this...