iphash does not send clients with the same source IP to the same backend

[nycterent]

I am experiencing similar issue, but I cannot fix it with my limited skills. I have multiple backends and using iphash balance method. My expectations are that all connections coming from specific ip would be sent to the same backend, but I can see that it is not the case (sometimes it works and sometimes does not):

2019-08-05 07:22:44 [INFO ] (execFetch): Fetched [{b.b.b.131:4500 p=1,w=1,l=true,a=0} {b.b.b.133:4500 p=1,w=1,l=true,a=0} {b.b.b.135:4500 p=1,w=1,l=true,a=0} {b.b.b.137:4500 p=1,w=1,l=true,a=0} {b.b.b.139:4500 p=1,w=1,l=true,a=0} {b.b.b.141:4500 p=1,w=1,l=true,a=0}] 2019-08-05 07:22:44 [INFO ] (execFetch): Fetched [{b.b.b.131:500 p=1,w=1,l=true,a=0} {b.b.b.133:500 p=1,w=1,l=true,a=0} {b.b.b.135:500 p=1,w=1,l=true,a=0} {b.b.b.137:500 p=1,w=1,l=true,a=0} {b.b.b.139:500 p=1,w=1,l=true,a=0} {b.b.b.141:500 p=1,w=1,l=true,a=0}] 2019-08-05 07:23:11 [DEBUG] (udp/server): Hash key:c.c.c.51:48959 2019-08-05 07:23:11 [DEBUG] (udp/server): Selecting backend: b.b.b.137:500 2019-08-05 07:23:11 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:11 [DEBUG] (udp/server): Selecting backend: b.b.b.137:4500 2019-08-05 07:23:11 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:11 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:11 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:11 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:12 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:12 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:12 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:12 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:12 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:12 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:12 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:12 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:13 [DEBUG] (udp/server): Hash key:c.c.c.51:51167 2019-08-05 07:23:24 [DEBUG] (udp/server): Hash key:c.c.c.51:20632 2019-08-05 07:23:24 [DEBUG] (udp/server): Selecting backend: b.b.b.133:500 2019-08-05 07:23:24 [DEBUG] (udp/server): Hash key:c.c.c.51:14903 2019-08-05 07:23:24 [DEBUG] (udp/server): Selecting backend: b.b.b.135:4500 2019-08-05 07:23:28 [DEBUG] (udp/server): Hash key:c.c.c.51:14903

I am guessing that somewhere outgoing port of the client is used in a hash

Using gobetween_0.8.0+snapshot_linux_amd64

Originally posted by @nycterent in #176 (comment)

[illarion]

Looks like the regression of the bug caused by random nature of golang maps. Backends are stored internally as map. Thank you for reporting