Signal-desktop: Signal desktop app does not work in IPv6-only environment.

[mdavids]

2327 still seems an open issue.

I have an IPv6-only system (with IPv4 disabled on my interface) and a NAT64/DNS64 setup to reach the IPv4-world. I can see the Signal desktop app is attempting A and AAAA queries for 'textsecure-service.whispersystems.org' (among other things, like 'cdn.signal.org' and 'updates2.signal.org') and then trying to prefer the A-record over the AAAA record, even though there is no IPv4-connectivity possible. This obviously fails. The AAAA answer is not used.

When I reconfigure my DNS64 resolver in such a way that an A-query gives a NODATA result, so that AAAA is the only reply returned, everything works. However, I can only do that in my own environment, not in other similar IPv6-only environments, maintained by others.

It seems to me that Signal (or Electron, or NodeJS for that matter) has no, or a dysfunctional 'Happy Eyeballs'-implementation. Could be NodeJS: nodejs/node#6307

Is this something that can be fixed?

[kenpowers-signal]

I can see a PR for node referenced in that issue: https://github.com/nodejs/node/pull/31567

Once a fix reaches Node and then eventually Electron this issue should work itself out after we update to that version of Electron. I don't think there's much else we can do on our end though.