Hi,
I am trying to run an obfs4 bridge on a Raspberry Pi 4 and would appreciate some clarification on whether my setup is supported.
For context, my host is behind CGNAT and does not have a public IPv4 address, but it does have a globally routable IPv6 address. I configured Tor as an obfs4 bridge and verified that the configured TCP port is reachable over IPv6 using the bridge reachability scan. However, after a couple of days, I do not see the bridge listed on Relay Search, and querying the bridge status page (https://bridges.torproject.org/status?id=) returns “no resources for the given id”.
This made me wonder whether IPv6-only obfs4 bridges are currently supported. I found the following statement in the Tor Support documentation: “For the time being Tor will require IPv4 addresses on relays; you can not run a Tor relay on a host with IPv6 addresses only.” At the same time, the tor manual documents the IPv6Only option, which seems to suggest that listening exclusively on IPv6 should be possible when no IPv4 address is available.
This has left me a bit confused about the current state of IPv6-only support, specifically for obfs4 bridges. Is it currently possible to run an obfs4 bridge that is IPv6-only? If not, is the lack of an IPv4 address sufficient to explain why the bridge is not appearing in metrics or status pages despite being reachable over IPv6?
Also, are there any recommended workarounds for users behind CGNAT who only have IPv6 connectivity?
For reference, here is the relevant portion of my torrc:
BridgeRelay 1
ORPort [::]: IPv6Only
ServerTransportPlugin obfs4 exec /usr/bin/obfs4proxy
ServerTransportListenAddr obfs4 [::]:ExtORPort auto
Thanks in advance for any support you provide.