[Telepathy] TURN servers in Empathy

[Simon McVittie]

On 24/01/15 19:04, Dominik George wrote:
> I cannot seem to establish calls in Empathy through XMPP/Jingle and our
> TURN server.

I don't think non-Google TURN servers are supported, either
automatically-detected or manually-configured.

> I found rumours here [1] that Empathy/Telepathy is using some Google
> relay server instead.

(Your footnote is missing, but I can guess.)

If you are using a Google XMPP account, telepathy-gabble will
automatically discover Google relay servers and propose them as a
low-priority "candidate". That candidate will be used if the
higher-priority direct connections (using STUN to get through NATs) all
fail. In this situation, you are already trusting Google to provide
security and privacy for your communication (for instance, it would be
technically possible for Google to edit the XMPP message stream and
replace all candidates with their relay), so using a Google relay server
does not represent additional exposure.

If the peer (the other person in the call) proposes a relay server
candidate, again, that candidate will be used if higher-priority direct
connections fail; so if you are not using a Google account, but your
friend is, then your data might end up going through a Google server. In
this situation you are already trusting Google to provide security and
privacy for your communication *with that particular friend* (if you
don't trust Google for that, then you need to ask that friend to change
their XMPP provider), so again, this is not additional exposure.

> Are all media streams routed through Google, and is there no option to
> change that?

Media streams are only routed through Google if

(a) the media stream is not getting through your NAT otherwise, and
(b) the relevant accounts are such that you are already required to
    trust Google to relay your XMPP data correctly (either all of it,
    or just that particular peer)

    S