Listening Port

Specifing the server listening ports are in following format.

-i 192.168.1.5

Single IP spec. If no port number is specified, defaults to 1080/tcp. Server socket will be 192.168.1.5 port 1080.

-i 192.168.1.5:9999

Single IP with port. Server socket will be 192.168.1.5 port 9999.

-i my.socks.host:5432

Hostname is also accepted.

-i :1234

No host IP or hostname is specified. Server socket will be INADDR_ANY port 1234.

-i '[2003:268:1234:4321:250:8bff:fea8:1234]:1234'

IPv6 address must be surrounded by '[' and ']'. In most of the cases, you have to escape '[' and ']' characters against your shell.

-i options can be appear multiple times if you'd like to have a lot of holes.

If no -i option is specified, default port is INADDR_ANY/INADDR6_ANY port 1080 .

Authentication method

The socks version 5 authentication is mechanism for authenticate the server user. The srelay only supports 'No Authentication' and 'Username/Password Authentication'. On the Username/Password authentication, the srelay using the server host's account information. For instance, using UNIX host's password database. This is deprecated if you are in the network with full of sniffers :) Why ? er, plain text password is launched by the client every time at connecting the server. I recommend not to use -ap option.

When the srelay is working as the intermediate of socks servers chain, it is some time required to use socks authentication to connect to next-hop socks server. In this case, you can specify the username and password for the next-hop socks by using srelay.passwd file. This is done whether you are specifing -a option or not.

srelay.conf

Configuration file format.
# this line is comment.
# destination port range next [next-p x-next x-next-p]
# subnet length
123.123.131.0/24 any 10.10.10.1
# subnet mask in doted format higher port is 65535
223.224.2.128/255.255.255.128 512- 10.11.22.1 11080
# lower port is 1
223.224.2.128/25 -511 10.11.22.2
# IPv6 destinations go through Gateway
:: - 100.200.1.1
# IPv4 destinations go through another Gateway
0.0.0.0 - 100.200.1.2
# (IPv6 to IPv4 destinations)
0.0.0.0 - 3002::1:4321:250:8bff:ffa8:1234
# no next-hop means connect direct.
1.2.3.4 -
#---

If a next-p (next-hop socks port) is ommitted, is defaulted to 1080, as you can guess. A next-hop socks port can be like, 8080/H or 8080/S, where H, S means HTTP, SOCKS, respectively. this also defaults to SOCKS.
HTTP relaying method is experimental, and supports minimized spec of HTTP Proxying.

You can be on your network environment like this.
[Client]-->(socks)[srelay]-->(http)[FireWall] -->(socks)[Socks_Island]-->[Dest]

srelay.conf setting could have the third Host, [FilreWall] like this.

# dest dest-port proxy proxy-p proxy2 proxy2-p
Dest any Socks-Island 1080 FireWall 8080/H

The listing order of proxy and proxy2 is farthest first order.

srelay.passwd

Username/Password information for connecting next-hop socks server.
# this line is comment.
# next-hop server username password
123.234.0.1 hogehoga xyz$12#
10.11.22.1 opopop tutut555