Wireguard peer generator forget to increment a new IPv6 address from previously used ones.

[noci2012]

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• I am convinced that my issue is new after having checked both open and closed issues at https://github.com/opnsense/core/issues?q=is%3Aissue

Describe the bug

A clear and concise description of what the bug is, including last known working version (if any).

This might have been here before. I added all previous wireguard profiles using all data entered by hand.
This was the first new fresh profile. (Note split off from a different feature request).

To Reproduce

Steps to reproduce the behavior:

1. Go to VPN > Wireguard > Peergenerator
2. Create a new system WITH IPv4 (.1/32) and IPv6 (PREFIX::1/128) address.
3. Save the profile and create a new one....
4. See error: missing IPv6 incremental address.

Expected behavior

Valid ext IPv6 address just like with IPv6

Describe alternatives you considered

Currently the next available address is like PREFIX:LOCALNET::/128 in stead of PREFIX:LOCALNET::12/128
when 1..11 already exist.... (help to keep IPv4 & IPv6 device IP's similar).

Screenshots

Too much privacy sensitive data in view. After editing nothing valuable there anymore.

Relevant log files

N/A

Additional context

N/A

Environment

Software version used and hardware type if relevant, e.g.:

OPNsense 25.7.10 (amd64).

[AdSchellevis]

/128 is a single address, details matter, hence the question for a reproducible case in the other ticket. (this isn't input someone can try in its own setup)

Our forum (https/://forum.opnsense.org) is likely a better place to discuss setup scenarios and instructions.

[noci2012]

Well here are redacted images.