srelay(8)srelay(8)NAMEsrelay - socks protocol server.
SYNOPSISsrelay [options]
DESCRIPTION
The srelay is socks version 5 server, including version 4 support.
The srelay has following features.
- socks version 5 connect/bind operation for TCP relaying.
- socks version 4 connect/bind operation, including FQDN extensions.
- series of multiple socks servers relaying with both version 4 and 5
servers.
- support username/password authentication.
- connection control with tcp_wrappers(libwrap).
- support IPv6 as well as IPv4 (hopefully).
- You can build IPv4 <-> IPv6 gateway with the srelay.
- nicely cope(relay) with NEC's SOCKSv5 reference implementation
servers.
- Free to use/distribute.
OPTIONS
The options are as follows:
-c file configuration file.
-i i/f Interface, or listening port. See Listening Port.
-m num Maximum child process for non-threading daemon. Or, number
of thread for threading daemon.
-o minutes
Idle transfer timeout in minutes. 0(zero) means no time‐
out(default.)
-p file PID file; stores main process or main thread process ID.
-u file srelay password file used in intermediate SOCKS5 server.
-a [n|p] authentication method.
n No Authentication.
p Username/Password authentication.
Authentication methods are evaluated in its placing order. If
this option is not present, 'No Authentication' method is
taken.
-f Run foreground. (not tested well :-p)
-r Try resolve client ip to name on logging.
-s Logging to syslog, even if running foreground.
-t Disable threading. (valid in thread-enabled configuration)
-b Avoid BIND port restriction.
-g Use the same interface for outbound as inbound.
-v Show version info.
-h -? Show help.
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 'User‐
name/Password Authentication'. On the Username/Password authentica‐
tion, 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
FILES
/usr/local/etc/srelay.conf
default configuration file.
/usr/local/etc/srelay.passwd
username/password information using in connecting to the next-
hop socks v5 server.
/var/run/srelay.pid
default PID file.
/etc/hosts.allow /etc/hosts.deny
(if supported in compile time,) tcp_wrappers configuration. TAG
name is 'srelay'.
SIGNALS
The following signals are meaningful:
SIGHUP reload srelay.conf.
SIGTERM
Exit.
SEE ALSOhosts_access(5),
RFC 1928 SOCKS Protocol Version 5,
RFC 1929 Username/Password Authentication for SOCKS V5,
http://www.socks.nec.com/socksproto.html
AUTHOR
Tomo.M <tomoyuki@pobox.com>
27 Mar 2003 srelay(8)
