Failed authentication log messages.

[sa6kad]

Hi.
First, great thanks for this great socks5 server, I use it all the time.

An idea about failed authentication log messages. currently it looks like this:
2023/05/26 15:02:55 [ERR] socks: Failed to authenticate: User authentication failed

If it was possible to add the source IP address to this log message it would simplify coupling this socks server with, for example, fail2ban tool to help against brute force and similar attempts.

Actually a connection attempt with the wrong password generates two messages:
2023/05/26 15:02:55 [INFO] socks: Connection from allowed IP address: 10.23.0.100
2023/05/26 15:02:55 [ERR] socks: Failed to authenticate: User authentication failed
So there is actually info about the source IP but having it in the same message would simplify parsing the log file.