Forward from: https://github.com/shadowsocks/shadowsocks-libev/issues/1915

What version of shadowsocks-libev are you using?
Master

What operating system are you using?
Debian

What did you do?
Connected from Shadowsocks client on Android, testing UDP relay

What did you expect to see?
on SS-Server when a bind address is specified with -b then TCP connections
outbound will use this address. I would also expect UDP outbound connections to
also use this address but they do not.

What did you see instead?
Source address of UDP datagrams leaving the ss-server are using the default IP
address NOT the -b Bind address.
Please could you fix so that UDP datagrams are always sent from the -b Bind
address just like TCP connections are.
There is a call to bind_to_address() when TCP sockets are created in server.c ,
but this is NOT called in udprelay.c when UDP sockets are created.
Thank you!