IPv6 Link local address in addresses?

Support
1

Is it possible to specify IPV6 link local address eg fe80::46fe:efff:fe1c:88c4%bnep0 as an address?

I use my computer via my phone and mostly tether using bluetooth unless I need something heavy. My phone’s bluetooth tethering gives me a different IPV4 subnet everytime my phone reboots or something but the link local IPv6 always stays the same. Is it possible to give a link local ipv6 address?

2

Yes, that should work out of the box.

3

My entry is tcp6://[fe80::46fe:efff:fe1c:88c4%bnep0]:22000

I get the following message in my syncthing UI

tcp6://[fe80::46fe:efff:fe1c:88c4%bnep0]:22000

invalid URL escape “%bn” (14:52:28)

Its very likely I’m doing something wrong here but it’s also that I don’t know what it is.

I unzipped the support bundle and the following is the version-platform file



{
  "arch": "amd64",
  "codename": "Hafnium Hornet",
  "longVersion": "syncthing v2.1.2 \"Hafnium Hornet\" (go1.26.5 linux-amd64) nix@nix 1980-01-01 00:00:00 UTC [noupgrade, stnoupgrade]",
  "now": "2026-08-05T14:54:39+05:30",
  "os": "linux",
  "version": "v2.1.2"
}

Over on repology, syncthing package versions - Repology the latest version green is 2.1.2 too.

What might I be doing wrong …?

4

Try replacing the % character with a %25, which is the URL-escaped form. I don’t know exactly how Syncthing parses the URL, but there is an ongoing discussion for years about how to specify the interface identifier in URLs. Most browsers currently just don’t support link-local IPv6 addresses in URLs for exactly this reason. The relevant IETF working groups / browser forum need to reach a consensus first, which seems rather unlikely by now.