Local auth works with dovecot-proxy, remote does not

[Camilo Sperberg]

Hi list!

I've configured dovecot-proxy to redirect users to another server if their
data is indeed on that other server.

Webmail (which runs on the same machine) works perfectly fine, but clients
such as Thunderbird and Outlook do not work as intended, I suspect it to be
a problem with the IP that dovecot-proxy sees, but I can't figure out what
is wrong: I've already done a lot of Googling and also tried to change the
login_trusted_networks value, but to no avail.

I've enabled debug log and here is the relevant part of a call that fails
and another one that succeeds (FYI 10.164.0.3 is the machine that is doing
the proxying and where webmail is located, 10.164.0.20 is the 'node', these
logs come from that node, doveconf -n is also provided in the gist):
https://gist.github.com/unreal4u/64de0f05b6e3b98034cdb0ae52ce1196

So as far as I can interpret the logs, in the failure case it is basically
saying it should go to the node, despite it already being on that node:
Aug 24 11:29:07 mail-node-2 dovecot: auth: Debug: client passdb out:
OK#0112#011user=me at XXXXXX.XX
#011host=10.164.0.20#011port=143#011proxy#011pass=<hidden>

In the success case, I don't see any mention of a proxy:
Aug 24 11:35:21 mail-node-2 dovecot: auth: Debug: client passdb out:
OK#0116#011user=me at XXXXXXXXX.XX


What am I missing here? Has this something to do with
authentication-allow-nets or authentication-allow-real-nets ? If so: where
to define it? Is there something else I'm missing?

Thanks in advance for your help,
Camilo Sperberg
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