Thanks for your message, candlerb.

There are some interesting tips within it which I will research further.

In reply to a post by candlerb:

Note that IPv6 by itself doesn't give you any help when changing provider, since you must use the IPv6 block assigned by your provider out of their address space - that is, you'll have to renumber all your IPv6 when changing provider.

I am not fully conversant with all of the ins and outs of this, but as I understand it, if you are setting ipv6 addresses manually, then you are not doing it right.

In reply to a post by Woolwich:

Meanwhile where to go? Only Aquis and IDNet seem to have fixed IPs and a decent reputation.

Both do ipv6 and Aquiss give you a /56 prefix. But IDNet did not even understand the question when I asked what size prefix you get and did not reply to an email.

Edited by DFScale (Wed 01-Jul-26 18:03:40)

In reply to a post by DFScale:

I am not fully conversant with all of the ins and outs of this, but as I understand it, if you are setting ipv6 addresses manually, then you are not doing it right.

For client devices, sure.

However if you are running servers or VMs, then it's standard practice to give them static addresses - for both IPv4 and IPv6. You *could* build servers which pick up their addresses via DHCP for IPv4, and SLAAC or DHCPv6 for IPv6, but it's not common practice.

In principle you could have a master "source of truth" database which generates both your DHCP configs and your DNS zones. That would allow central renumbering, but it's a lot of work to build - and adds a critical piece to your infrastructure.

There are service providers which give you a different IPv6 block each time you connect. For those, dynamic numbering is essential, but I wouldn't want to run any servers on a network like that.

Just for info, Zen are inflexible and couldn't possibly delay this change. This is the message I got back from them:

We periodically review how our IPv4 address space is allocated to ensure it is managed effectively across our network and customer base.

As part of this ongoing programme, we are working to standardise and simplify legacy allocations. This approach helps us improve efficiency while ensuring that customers continue to have the address capacity they need to support their services. There is no way we can delay this. Please accept my apologies.

For existing consumer customers who currently have multiple IP addresses free of charge, if they wish to retain those IPs, we can arrange for an order to be placed so the addresses can continue to be provided on a paid basis. This allows us to maintain the service while balancing commercial considerations and helps avoid any disruption to the customer experience.

We currently offer the following options:

1 IPv4 Address – Included in your tariff
8 IPv4 Addresses – £13.20 per month (including VAT)
16 IPv4 Addresses – £28.20 per month (including VAT)
32 IPv4 Addresses – £58.80 per month (including VAT)
64 IPv4 Addresses – £118.80 per month (including VAT)

If you would like to proceed, please let us know which block size you require and we can arrange this for you.

Seems like they're just money grabbing. Aquiss will do a /29 at extra cost (but less than Zen) and include a /56 IPv6. As soon as things are more convenient timing wise, I will be off from Zen as they've burned their bridges.

I had a /29 from the outset as part of my service (it's listed in the original order confirmation), they now seem to be implying that this was a freebie that now needs to be paid for. I am long out of my minimum term, if I wasn't then I would consider this a material change and a good reason to end the contract without penalty.

Looks like Zen have breached their Lifetime Price Guarantee!

1. What is the Lifetime Price Guarantee and how does it work?
The Lifetime Price Guarantee applies to fixed monthly price of eligible broadband and line rental services
for customers who entered into a contract with Zen before 31 May 2022. As long as you stay on that
same service and contract at the same location the price for that service will not change.

I have asked them why they think they haven't!

In reply to a post by zeb99:

Aquiss will do a /29 at extra cost (but less than Zen) and include a /56 IPv6.

To be fair, Zen also include a /56 IPv6 for free for all users who want it.

You can argue with Zen that your lifetime price guarantee included the extra IP allocation, but if they continue to say no (and I suspect there are terms in the T&Cs that allow them to make variations to the service), then I don't think there's much you can do except walk.

Zen are going to force you to renumber anyway, so you might as well renumber to a different service provider's address space.

Remember that Zen are playing a numbers game here: the number of customers who care about their static IP address allocation is vanishingly small across the total user base (which is mostly non-technical households who follow Which? recommendations). If they lose some of those customers, Zen don't care: it will be essentially invisible in the total user figures

The thing that matters to Zen is that they complete their IP address consolidation and resale, and they probably have a contractual date for handing over the addresses.

Zen seems to be playing fast and loose with contract law.

Zen appears to be claiming that legacy IP allocations are not part of customers' contracts and were an additional free service, which they are now withdrawing for those in affected IP blocks. This is a very dubious interpretation, given that Internet access cannot function without IP addresses.

Commercial considerations, which Zen cites as its justification, are not grounds that permit Zen to alter the contract unilaterally under clause 14.5 of its standard terms and conditions. "Operational reasons" is a permitted reason for unilateral alteration, but it is hard to dress up this withdrawal of routed IPv4 as a genuine operational necessity. Like-for-like renumbering is arguably an operational reason, but saying you have to pay extra is a commercial reason, not an operational one.

Zen's right to unilaterally alter terms via clause 14.5 is rather broad in nature and seems unlikely to be fair for the purposes of Part 2 of the Consumer Rights Act 2015. The only mitigation of clause 14.5 - and the only hope of it being fair and therefore enforceable against the consumer overall - is the right to disconnect without penalty on a change that amounts to substantial disadvantage in clause 14.7.

We are only in the second month of a 24-month contract after a recent upgrade from FTTC to FTTP. Worse still, Zen have put the digital voice service back into a 24-month minimum contract on the day the FTTP started. At this point, I am done with Zen after nearly twenty years, IIRC (look back at my posting history here as David_W), and intend to request disconnection via clause 14.7. The phone will go to Andrews and Arnold, and I may well go to Andrews and Arnold for FTTP, especially as I currently have a /28 (for which I had to provide a RIPE form and pay Zen a one-off fee). I am going to try to rearrange my network so I only need a /29, but I cannot cope without routed IPv4.

In reply to a post by David_W2:

Zen seems to be playing fast and loose with contract law.

I agree. I think your analysis is spot on.

In reply to a post by David_W2:

... especially as I currently have a /28 (for which I had to provide a RIPE form and pay Zen a one-off fee). I am going to try to rearrange my network so I only need a /29, but I cannot cope without routed IPv4.

You should probably look on this as a stopgap and plan to transition to IPv6. Given the haste with which Zen are doing this, as @candlerb says it looks like they have already sold the addresses on. I can only envisage the pressure on IPv4 addresses increasing until the point where everyone gives up and moves to IPv6 for static addresses.

I have never needed more than a /32 and never needed a fixed IP, although my ISP gives me one. But whatever I do now, I would make fit with the constraint of CGNAT for IPv4 and a /56 for IPv6

In reply to a post by DFScale:

You should probably look on this as a stopgap and plan to transition to IPv6. Given the haste with which Zen are doing this, as @candlerb says it looks like they have already sold the addresses on. I can only envisage the pressure on IPv4 addresses increasing until the point where everyone gives up and moves to IPv6 for static addresses.

I have never needed more than a /32 and never needed a fixed IP, although my ISP gives me one. But whatever I do now, I would make fit with the constraint of CGNAT for IPv4 and a /56 for IPv6

I have been using IPv6 for so long that I have an allocated /48 from Zen. I have deliberately only ever used the lowest /56 of that /48, as I knew all along I would never need more than a /56 (256 /64s is likely to be more than enough for all but the largest networks). It would be trivial to rearrange my system to a /56 allocation.

The problem with IPv6 is how slowly the rest of the Internet has adopted it and how many devices and services still support only IPv4. All my end-user devices, servers, switches, wireless APs, and my main HP MFP support IPv6, but nothing else does (solar inverter, a couple of label printers, a network scanner, and various IoT devices). Vodafone still does not offer IPv6, so most of the time when I am away from home, I can only VPN into my network using IPv4. My backup ISP, Virgin Media, still has not enabled IPv6 in my region.

CG-NAT is totally unsuitable for me; I need incoming IPv4. I cannot rearrange everything into a /32, as that would leave me with clashing ports. I will try to rearrange my network into a /29 over the next few days, as running with the fewest possible IPv4 addresses makes sense.