Proxy issue - Failing proxied request for user error

[James Wood]

Dear Group,

We have a proxy-based setup but need advice on dropped proxy requests. We
were running on 3.0.12 and upgraded to 3.0.19 but not change in behaviour.

It's a simple one to one proxy, so packets come in to an external RADIUS
server (public IP) and traffic is proxied to an internal one.

We are seeing random errors for accounting packets but I can't figure out
why. I ran a tcpdump on both sides and can see the traffic is being sent
from the master and received on the internal server. But, the internal
server must not be handling it nicely it as the master server says:

Fri Jul 12 07:38:01 2019 : ERROR: (259008189) ERROR: Failing proxied
request for user "689c3148b5a04d73a931534f0dd46f35", due to lack of any
response from home server 10.0.0.1 port 1813
Fri Jul 12 07:38:01 2019 : ERROR: (259008191) ERROR: Failing proxied
request for user "f1680ea08fff4773b415a4a4a34b9365", due to lack of any
response from home server 10.0.0.1 port 1813
Fri Jul 12 07:38:01 2019 : ERROR: (259008193) ERROR: Failing proxied
request for user "3b710ab2b4b0497baadd543582b7afc6", due to lack of any
response from home server 10.0.0.1 port 1813
Fri Jul 12 07:38:01 2019 : ERROR: (259008194) ERROR: Failing proxied
request for user "0f2eec41a0b7488a88d6dc131913538d", due to lack of any
response from home server 10.0.0.1 port 1813
Fri Jul 12 07:38:01 2019 : ERROR: (259008195) ERROR: Failing proxied
request for user "0c02bd6c5fb2426ea981fa62c51099eb", due to lack of any
response from home server 10.0.0.1 port 1813
Fri Jul 12 07:38:01 2019 : ERROR: (259008196) ERROR: Failing proxied
request for user "6d6749a71aaf49ec97c472f85af18158", due to lack of any
response from home server 10.0.0.1 port 1813
Fri Jul 12 07:38:01 2019 : ERROR: (259008197) ERROR: Failing proxied
request for user "39fd72831dbd4236abc055f01bea0d5b", due to lack of any
response from home server 10.0.0.1 port 1813
Fri Jul 12 07:38:01 2019 : ERROR: (259008198) ERROR: Failing proxied
request for user "1c4c86da12054a099af44d4f0780b666", due to lack of any
response from home server 10.0.0.1 port 1813

Notes:
1) The server handles around 50-100 auths/acct packets per second, so
nothing major. The  majority of requests are proxied without error and the
failed ones are not from the same NAS client, spread out across many.
2) This only happens on accounting packets, never auths
3) It happens on Start, Stop and Interim packets
4) It seems to happen in chunks, i.e. i'll get a big block of 30 or so of
these errors appear in the lock

Any help on how to debug would be much appreciated.

Thanks

J