Disable ipv4 address sharing (map-t)

[domb84]

So sky have forced map-t on its users meaning that most 3rd party routers are now paperweights. This article suggests that customers can request its disabled. I've requested this twice and support have no idea what im requesting. How can i get this disabled?

https://www.ispreview.co.uk/index.php/2024/06/isp-sky-broadband-uk-deploying-ip-address-sharing-via-...

"UPDATE 14th June 2024 @ 7am

Sky UK has kindly responded to confirm the information we’ve posted above and that their solution will be able to proactively opt-out customers from IPv4-sharing where it will hinder their user experience, so customers should not be impacted by these changes."

[Chrisee]

@domb84there is no indication that users of third party routers will be negatively impacted. If the router supports MAP-T as many do then it can be involved. If it doesnt support MAP-T as the black Sky hub 4 doesn't then it remains on the standard set up. 

Sky customer services are not directly involved in the roll out which in the main is transparent to users the only observable issues are with some VPN users with the new white Sky Max hubs which can be sorted by switching the ratio from 8:1 to 1;1.  

[domb84]

Unifi do not support map-t. Using the unifi i'll get an ipv4 address after anywhere between 1-24 hours, then it will randomly lose it anywhere from 2-4 days later leaving me with no internet access. I never receive an ipv6 address during that period either. The only solution is to use the sky hub ive found. Even this if you choose to configure your own internal subnet rather than use 192.168.0.0/24, the hub sets itself back to 192.168.0.1 after a few days regardless.

[-rpnz-]

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@domb84 wrote:

So sky have forced map-t on its users meaning that most 3rd party routers are now paperweights.

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Hi @domb84 

MAP-T isn't being forced, MAP-T will only be given to CPE routers that ask for it.

However, Ubiquiti's Unifi routers do have a known issue, where they ask for MAP-T but don't actually support it.

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@domb84 wrote:

Unifi do not support map-t. Using the unifi i'll get an ipv4 address after anywhere between 1-24 hours, then it will randomly lose it anywhere from 2-4 days later leaving me with no internet access. I never receive an ipv6 address during that period either.

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These symptoms, however, sound a bit different to what I'd expect, and there may be additional or just other issues going on here.   If you were hitting the Unifi/MAP-T issue, you would have a DHCPv6 PD lease (IPv6 prefix), and you would have a DHCPv4 lease with an unusable IPv4 address from the 100.64.0.0/10 prefix.   The quick fix here would be to disable DHCPv6 PD on the Unifi's WAN interface and fall back to single-stack IPv4-only; the longer-term proper fix would be for Unifi to either not ask for MAP-T, or to start supporting MAP-T.

[domb84]

Thanks for the information. This is exactly what happens. It falls back to a 100.64.0.0/10 address.

If i set ipv4 only and disable ipv6 it works for a few days but then its as though the lease expires and connectivity is lost for hours. Once for 2 days. Then all of a sudden I'll receive a new v4 lease and all is well again.

Something is very odd...

is there some detailed documentation on interface configuration? 

[domb84]

FYI although the unifi reports a 10.64.0.0 address, at no point has it reported getting a v6 address. I configured for a /56 delegated prefix. 

[TimmyBGood]

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@domb84 wrote:

 This article suggests that customers can request its disabled. I've requested this twice and support have no idea what im requesting. How can i get this disabled?

"UPDATE 14th June 2024 @ 7am

Sky UK has kindly responded to confirm the information we’ve posted above and that their solution will be able to proactively opt-out customers from IPv4-sharing where it will hinder their user experience, so customers should not be impacted by these changes."

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Actually that quote is saying the system automatically opts-out customers under certain circumstances where these are detected, and your use of a non-Sky router probably prevents that happening.

You'll need to persist with contacting someone in support who's aware of the situation.  I'll try escalating your original post.

[-rpnz-]

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@domb84 wrote:

If i set ipv4 only and disable ipv6 it works for a few days but then its as though the lease expires and connectivity is lost for hours. Once for 2 days. Then all of a sudden I'll receive a new v4 lease and all is well again.

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Sounds like you're missing DHCPv4 Option 61, which allows us to authenticate your service using DHCPv4, and instead are relying on DHCPv6 (which then has the MAP-T issue).  Have a browse of the forums for other threads discussing 3rd party routers.

Edit: Sorry I missed the last bit where you said "and then all is well again", in which case it's just the switchover.  If you leave DHCPv6 disabled, you will not get MAP-T again and should not have anymore issues. (of course the down side is you no longer have IPv6 connectivity)

[Lisa-P1987]

Thanks for escalating this. We’ve sent domb84 an invite to chat.

[domb84]

I should say its all well for another couple of days or until the router is rebooter, physically disconnected and then it all starts again. I tried various combinations of option 61 and trying to guess your auth mechanism. It didnt seem to matter if it was encoded, clear text, various combinations of enaill address options. The only difference seemed to be that your connectivty checker seems to think its ok if I specify it (yet i have no public ip so not sure how that works), and without it seems to think ive unplugged my router. Will follow up on the dm. Thank you!

[Earnys10]

So they've now basically opened doors to attack vectors. 

This is such a bad security vulnerability just to save a few pounds. I was completely unaware about these changes. 

[TimmyBGood]

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@Earnys10 wrote:

This is such a bad security vulnerability just to save a few pounds.

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IPv4 simply doesn't have enough addresses for global use over the rest of this century: its inventors couldn't realistically have anticipated the need in the early 1980s.

IPv6 has to happen.

[Ash_scfc]

Hello, i have spent the last 2 days with connectivity issues on my work supplied laptop.

Its gone high up to our network tech people (i work for one the worlds biggest insurance brokers) and they've tracked it down to MAP-T being enabled on my Sky Max Hub.

How do i opt out of this, i have not been able work for 2days now?

[TimmyBGood]

@Ash_scfc 

That requires individual attention, so I'll escalate your post.

[Addie15]

Hi there! Thank you for escalating this. We have sent an invite to @Ash_scfc.