Hello,
we are using Nginx to load-balance UDP-based DNS queries to a number of upstream servers. The client side, which is not under our control, often uses fixed UDP source ports to avoid overloading stateful firewalls.
Before version 1.15 of Nginx every query packet was usually forwarded to a different upstream, but with version 1.15 of Nginx this no longer seems to be possible because of this feature:
" *) Feature: now the stream module can handle multiple incoming UDP
datagrams from a client within a single session."
While we understand, that it is a great improvement for many UDP based applications, for us it is causing uneven distribution of DNS queries/work load to upstreams.
Our request would be to add a possibility to retain to the former behaviour. LVS/Ipvadm calls it "one-packet scheduler". The suggestion would be a configuration switch to modify the session behaviour, so that every request packet could be forwarded to a different upstream.
Thank you for providing this excellent software!
Best Regards,
Patrick Beckmann
tyntec GmbH, Germany
