UDP load balancing and ephemeral ports

[bwmetcalf@gmail.com]

Hello,

A couple of questions regarding UDP load balancing.  If a UDP listener is
configured to expect a response from its upstream nodes, is it possible to
have another IP outside of the pool of upstream nodes send a response to the
ephemeral port where nginx is expecting a response?  I'm pretty sure the
answer is no and the response has to come from the IP where the request was
forwarded, but wanting to verify.  We have a use case where another part of
our backend system could possibly send that response if coded to do so, but
I'm pretty sure this simply will not work.

Secondly, how long will nginx keep the ephemeral port open waiting for a
response from the upstream node where the request is sent and is this
configurable?   It looks like proxy_responses might be helpful in quickly
terminating a session after the desired number of responses are received?

Thanks.

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,280540,280540#msg-280540