How to get rid of a linked IP without deleting the profile

(TLDR at bottom, Also if you want, you can skip my rambling preamble and just go to the steps below)

So on my nextdns profile, I linked the IP address programmatically a while ago because I thought that was the only way I could get it working with protonvpn on my desktop. On android, I originally used the DNS over TLS endpoint through android's Private DNS setting, since Private DNS only lets you enter a DNS-over-TLS hostname and doesn't let you enter an actual IP address. The problem is that I ran into situations like university Wi-Fi where the DNS over TLS port is blocked while DNS over HTTPS still works. While trying to figure out a way around that, I found out that nextdns has IPv6 endpoints and that the IPv6 endpoint is directly tied to my nextdns profile. I had also assumed the custom DNS field in the protonvpn app only accepted IPv4 addresses, so once I realized I could put the IPv6 address in there too, I realized I didn't need the programmatic IP linking after all and could just use the IPv6 endpoint directly.

Now that I've got the IPv6 setup working now, I wanted to get rid of the old linked IP. Since leaving a public IP linked can be a bit of a privacy or at least spam nightmare, since if other people end up using that IP later, their traffic can get associated with your profile and you can end up with logs and stuff from people you don't even know.

Since nextdns doesn't give a way to unlink it, delete it, or change it manually (they should please), the only way I could find online to get rid of it was to duplicate the profile, since the new profile wouldn't have the old linked IP. That does work, but it's a hassle because then you have to go through all of your devices and settings and reassign everything to the new profile. I have a bunch of devices and a bunch of things configured around my current profile, so I really didn't want to go through all of that if there was a way to change it to a safe dummy address like 127.0.0.1.

After testing I ended up figuring out a workaround using DDNS and tested it on a disposable profile first to make sure it worked. It is also repeatable if you want to use it again in the future.

Here's what I did:

1. Create a DDNS hostname that you can edit (I used a free dedyn.io hostname from deSEC)
2. Make sure the hostname's ‘A’ record points to your current public IPv4 address Example: your-test-name.dedyn.io → xxx.xxx.xxx.xxx
3. In nextdns, go to Setup → Linked IP → DDNS and add the hostname
4. Once nextdns shows the DDNS hostname as active, change the hostname's ‘A’ record to 127.0.0.1
5. Leave the DDNS hostname attached and wait for nextdns to update the linked IP (You might need to wait a bit and do a couple refreshes until the setup page linked IP changes to 127.0.0.1)
6. Once the linked IP has changed to [127.0.0.1](), remove the DDNS hostname from nextdns
7. Refresh the setup page again to make sure it stayed as 127.0.0.1

Now you have a linked IP address that will always be 127.0.0.1, and you don't have to worry about DDNS if you don't want to use it lol.

IMPORTANT READ THIS – DON'T CHANGE THE ‘A’ RECORD TO 127.0.0.1 UNTIL AFTER NEXTDNS HAS ACCEPTED THE DDNS HOSTNAME. Once it's accepted, you can change the record and let the DDNS update happen. Otherwise you're gonna have to start the process over again.

Also, I know not everyone using nextdns wants to get super into the networking side of things, so for yall don’t worry, 127.0.0.1 is safe to use here. It's called localhost and it's the address that points back to the device itself rather than out to the public Internet. So if something connects to 127.0.0.1, it's connecting back to itself, not to somebody else's device

TLDR

Add a DDNS hostname while it points to your current public IP → change the hostname's ‘A’ record to 127.0.0.1 → wait for nextdns to update → remove the DDNS hostname