ES12's profile

Contributor

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14 Messages

Tuesday, March 28th, 2023 9:37 PM

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IPv4 Address

How do I keep my IPv4 address when switching to the newest XFi modem?  I have an XB6 now and returned an XB7 a few years ago because it came with an IPv6 address and no one at support could help me.  I have just receive the new XB8 and want to make sure I keep my IPV4 address before I go through the hassle of switching out the modems.

Accepted Solution

Expert

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107.2K Messages

2 years ago

You get both. The Comcast system is dual stack.

Official Employee

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352 Messages

2 years ago

Thank you for reaching out to us today over our Xfinity Community Forums! Please remember that sending unsolicited direct messages to an Official Employee of the Xfinity Help & Support Forums is a violation of Forum Guidelines. It really helps us if you create a new post on the forum first, and then send a direct message.

Contributor

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14 Messages

@XfinityMarcella​ 

I am not sure why this message was posted. I never sent a pm to anyone about this issue. This post was a brand new post about this issue???

Gold Problem Solver

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26K Messages

2 years ago

How do I keep my IPv4 address when switching to the newest XFi modem? ...

If you were using the old and new Comcast devices in bridge mode you'd keep the same public IP. But when using them in their standard router mode there's no way to avoid an IP change.

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

Contributor

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14 Messages

2 years ago

I have had the same IPv4 address for 9 plus years using xfinity/Comcast modems in DHCP mode. So, why can’t I keep my same IPv4 address with the new XB8?

Contributor

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342 Messages

Hello @ES12 thank you for reaching out through our forum. I apologize, but the IP address does change when using a new modem. We are not able to keep the same IP address when switching modems. Please let me know if you have any questions or how I can assist you further. 

I no longer work for Comcast. 

Gold Problem Solver

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26K Messages

2 years ago

... why can’t I keep my same IPv4 address with the new XB8?

DHCP uses the MAC address of the first device it encounters beyond the modem when it assigns an IP address. For Comcast gateways operating as they normally do this will be the MAC address of the gateway's router component. The new gateway will present a different router component MAC address to the DHCP server, which will then issue a different IP address.

It would be technically possible for Comcast to override this, but they don't seem to be willing to do that for you.

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

Contributor

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14 Messages

2 years ago

But can I get an IPv4 address and NOT and IPv6?

Contributor

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200 Messages

2 years ago

Why don't you want IPv6?  Normally you just get both IPv4 and IPv6 addresses.  It's possible to run an IPv4 only setup, but you'll need a router that supports disabling IPv6.  I'm pretty sure that means buying your own equipment.  Disable IPv6 is a common option on routers but I'm betting you can't do it on an XB8.

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