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Visitor

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3 Messages

Saturday, May 28th, 2022 2:08 AM

Closed

IPv4 to IPv6 changes

As a residential customer, I have a computer that I could sign into from the public side of my Linksys WiFi router. However, a few days ago, Comcast changed my public IP address from IPv4 to IPv6. Everything is working except my ability to access my LAN from the public side of my router. Linksys says I need some information that only Comcast can provide, but technical support keeps blaming my Motorola Surfboard modem, which I believe is wrong. Here's what I need, according to Linksys:

1) Network setup prefix:

2) Prefix length:

3) Border relay: (I'm thinking it's an address)

4) IPv4 address mask length:

Problem Solver

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788 Messages

3 years ago

Thanks so much for taking the time to reach out to us regarding your Router configuration. To better assist you can you advise what you are attempting to do? Are you trying to go back to an IPV 4 address or set up a static IP? 

Visitor

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3 Messages

3 years ago

No, I'm not trying to keep using IPv4 or get a static, public IP address from you. All I really want to do is access the computer I have connected to the private side of my wifi router, < edit, personal information>, from the public side. . .  Until about a week ago, that access was quite simple, even when there was some kind of outage that caused my public IP address to change. I would learn the new IPv4 address, change it in Putty, and I was back in business. Last week, there was a system outage or perhaps an upgrade that caused my IP address to change. This time, however, after changing the IP address in Putty to the new one, < edit, personal information> I got "access denied" when trying to SSH into my computer. From there it was "down the rabbit hole," trying to get reconnected. I'm quite sure now that I was misleading myself about the symptoms and landed on the idea that it was the switch to IPv6 that's causing my trouble. So, I began looking for help from Linksys and Comcast. Actually, I've lost confidence in the advice given to me by Linksys because the menu item where the four pieces of information are "required" are not accessible by users like me. So, I have to begin again, this time looking more closely at my computer to see it it's corrupted.

I do have questions for you:

1) Can I use the IPv4 address, < edit, personal information>, which is my public side IP address assigned to me by Comcast, to gain access from the public side, to my computer on the private side?

2) Should I stop using the IPv4 address and switch to the IPv6 address?

Thank you for responding,

< edit, personal information>

(edited)

Problem Solver

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828 Messages

@user_01337d

 

Sounds like you are trying to enable port forwarding, and with port forwarding, you must use an Ipv4 address to connect to a network. If you are using a Xfinity Gateway modem, please confirm that you did not set a static IP for the device, using the Gateway Admin page (10.0.0.1). If you did, please remove the that, and the Xfinity app will use an IP address to establish the port forward. If you are using your own modem, check with the manufacturer of your modem on how to disable Ipv6 and set Ipv4 as "Preferred." You can learn more about port forwarding at https://comca.st/3t5QYpr.

I no longer work for Comcast.

Visitor

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3 Messages

Sounds like port forwarding is now done in the modem and not in my wifi router. If I upgrade to the rented modem, what happens with my Linksys wifi router? Is it now just a switch? Is it no longer needed, and I can get rid of it?

Problem Solver

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828 Messages

@user_01337d

 

You can still use your own personal router with the Xfinity Gateway modem. There are people who have a need that requires them to do that. 

 

I no longer work for Comcast.

Expert

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110K Messages

3 years ago

@user_01337d 

An FYI. If you do hang a separate / standalone router off of the Comcast rented gateway device, then you'll need to put the gateway in to bridge mode so that it acts only as a straight / plain vanilla cable modem (no routing / WiFi functioning);

https://www.xfinity.com/support/articles/wireless-gateway-enable-disable-bridge-mode 

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