Everything I can see suggests Giganet don't use OpenReach. Are you sure it isn't a CityFibre connection? If you look on OpenReach only ISPs like EE do they offer you a FTTP service?

See there was this post in february where someone was being transferred by Giganet to Home Telecom - has your service been moved which could explain the change in IP provision?

Thanks for the explanation. Would now being behind CGNAT break using a Dynamic DNS host name from noip,com? I've rebooted the router a few times and the portal at noip.com doesn't show the IP associated witht he host name being updated. And if I were to move to a different ISP is there any way to tell if they use CGNAT or not?

It is 100% certain an Openreach connection as that;s the only option here. Online checkers for Zen, EE etc all show FTTP availablity. I do remember that post about Giganet transferring customers to Home Telecom but I thought that was FTTC customers as up until a couple of days ago nothing had changed on the service provision. Billing was moved to Cuckoo Fibre a month or two ago but no change in service until now.

In reply to a post by sjr:

Thanks for the explanation. Would now being behind CGNAT break using a Dynamic DNS host name from noip,com? I've rebooted the router a few times and the portal at noip.com doesn't show the IP associated witht he host name being updated. And if I were to move to a different ISP is there any way to tell if they use CGNAT or not?

Yes, it would break your DDNS as: 1) the IP address you are seen from on the internet will change far more frequently so it may frequently be wrong and; 2) regardless of this, you can never connect back to your home network via this hostname / IP address because of the dual-NAT. The IP address you are seen as is not your router's address, but the address given out by your ISPs CGNAT gateway.

Most ISPs will advertise whether or not they use cgnat, but otherwise it's a case of Googling for them, or you may be able to find a list on here somewhere. If they offer an additional charge for a static IPv4 address, then it's quite likely they use cgnat for all customers not paying this extra charge.

In that case I agree with the previous poster who said to use it as a reason to leave the contract and move to someone else - there are plenty of options out there. If CGNAT is not viable for you and Giganet won't move you back to a dynamic or static IP then tell them it is a material change to your contract and you want out (that is assuming you are in contract).

In reply to a post by ian72:

In that case I agree with the previous poster who said to use it as a reason to leave the contract and move to someone else - there are plenty of options out there. If CGNAT is not viable for you and Giganet won't move you back to a dynamic or static IP then tell them it is a material change to your contract and you want out (that is assuming you are in contract).

Sadly I would be surprised if there has been a material change to the contract unless the type of IP is specified in the contract. Normally the contract gives them the right to do what they want.

Also see daern's answer but for others reminder that DDNS only updates a DNS entry for the apparent public IP your traffic is coming from, and does not of itself open any port forwarding or firewall rules.

In the case of CGNAT, there are updated protocols for customer routers to request that that the upstream CGNAT device forward a port (or range of ports) but not easy to find out unless the ISP provides good support or documentation about this.


There is a less common variation where the ISP assigns a static range of ports to each subscriber
(e.g 100 ports each for 480 subs per CGNAT engine IP would be 48000 with about ¼ of the ports left dynamic).
Terrible example but you get the idea how rough it is if too many customers behind a single IP.

Edited by prlzx (Thu 01-Aug-24 13:30:37)

In reply to a post by prlzx:

There is a less common variation where the ISP assigns a static range of ports to each subscriber
(e.g 100 ports each for 480 subs per CGNAT engine IP would be 48000 with about ¼ of the ports left dynamic).
Terrible example but you get the idea how rough it is if too many customers behind a single IP.

But of course you still have to worry that noone else using that IP misbehaves and gets the IP address blacklisted anywhere...

CGNAT. Ngggg :-/

Post deleted by naylor2006

I think i'd pay the 3 quid to be honest.....sure if you can get out of your contract due to a material change like some other folks have suggested then maybe do that....but if your IP is really important you can pay for a static which is better than the dynamic one you had before.

I deleted me post before because I accidentally replied to myself.