NAME

SYNOPSYS

DESCRIPTION

In order to determine if a given host is running an open proxy service, proxycheck tries to connect to a given destination system via a host and perform some actions, trying to talk with the destination system. If a talk is successeful, proxycheck assumes the proxy service is running and wide-open.

proxycheck supports all commonly used proxy protocols, namely, HTTP CONNECT method, SOCKS versions 4 and 5, and Wingate "telnet"-style proxies. In future, support for more protocols may be added.

Please note that with current number of various trojan horses cicrulating around, each opening a proxy on a random port, it is not really enouth to probe for standard (in whatever reason) ports built into the proxycheck. Instead, it is highly recommended to use a list of currently active ports maintained by several people on the 'net.

OPTIONS

-h

print a short help and exit.

-v

increase the verbosity level. All debugging messages will go to standard error stream.

-d deshost:destport (required)

try to establish a proxied connection to the given dsthost, port dstport. This option is required.

-c check[:params] (required)

the "method" proxycheck will use when talking to a destination system to determine if a proxy is open or not. Interpretation of params is check-dependant. This option is required. Several methods are available:

-p proto_port_spec

specifies protocol and ports to connect to. If not given, proxycheck will try it's built-in default list. This option may be specified more than once. See below for proto_port_spec. If proto_port_spec is specified for a single host to check, it applies to that host only, and no protocols/ports in default list will be checked for that host.

-D

do not reset default port list when using -p option, but prepend new ports to it instead.

-a

use more "advanced" ports/protocols. The more -a's given, the more ports/protocols will be probed. For a complete list of all ports and protocols and their level, execute proxycheck with -h option.

-t timeout

a timeout, in secounds, for every operation. Default value is 30 secounds. The timer starts at the connection attempt to the proxy itself, after sending the "connect" command to the proxy and so on.

-m maxconn

Do not attempt to make more than maxconn parallel connections. By default, maximum number of parallel connections limited by the operating system and on most systems it is around 1000.

-M maxhconn

Do not make more than maxhconn parallel connections to the same host (default is unlimited). This may be useful for overloaded proxies which can't handle many parallel connections using different ports/protocols, but may significantly slow down the whole process.

-s

when an open proxy is found on a given IP, stop probing for other ports/protocols for this IP. Best used when many IPs are tested, and/or with -M option. This is because currently, proxycheck will not make any new connections to such host, but will wait for already active connections to complete.

-b bindaddr

use bindaddr as a source address for all outgoing connections.

-n

write a line about definitely closed proxies to stdout in additional to writing about open proxies, in a form

   127.0.0.1 http:8080 closed
    

-x

print extended proxy information (proxy-agent and the like) if available. This will be on the same "open" (or "closed" with -n) line, last, enclosed in square brackets [].

-i filename

read list of hosts to check from a given file filename (in addition to command line), or from stdin if filename if `-'.

      [proto:][port,port,port]


like:
      hc:3128,8080 (http protocol on ports 3128 and 8080)
      hc:    (default list of ports for http protocol)
      3128   (try http protocol on standard http port 3128)
      1234   (try all protocols on non-standard port 1234)

USAGE

  proxycheck -d yourmailserver.example.org:25 \
    -c chat::greething ip.add.re.ss...

proxycheck will write a single line for every proto:port it finds to be open on stdout, in the form:

  127.0.0.3 hc:80 open

In addition, if proxycheck is able to guess outgoing IP address of a proxy as seen by a destination system, and if that address is different from input proxycheck is connecting to, it will print this information too on the same line, like:

  127.0.0.2 hc:80 open 127.0.0.3

When -n option is specified, for proto:ports which aren't running open proxy service, and for which proxycheck is able to strongly determine this, a line in the following format will be written:

  127.0.0.4 hc:80 closed

When -x option is specified, there will be additional proxy info written on the same line (if available), like:

  127.0.0.2 hc:80 open 127.0.0.3 [AnalogX 3.1415926]
  127.0.0.3 hc:80 open [AnalogX 3.1415926]
  127.0.0.4 hc:80 closed [AnalogX 3.1415926]

One may see some detail of proxycheck's operations giving sufficient number of -v options in the command line. Verbosity level of 5 (-vvvvv) will show almost everything. All the debugging output will go to the standard error stream and thus will not affect normal operations (when you process proxycheck's output using some script).

EXIT CODE

EXAMPLES

  proxycheck -vv -ddsthost:dstport -c chat::"waitstr" list-of-IPs

where dsthost is the host and dstport is the port number of the destination system, and waitstr is a string to look for from the remote system. If you decide to connect to your own mailserver (which is quite logical, since most proxy abuse nowadays is to send spam to your mailserver), connect to it first using telnet and see which SMTP greeting string it prints out upon connection, and use this string as waitstr. For example, if your mailserver is mail.example.com, the following may apply:

  $ telnet mail.example.com 25
  Telnet: trying 127.0.0.1... connected.
  250 mail.example.com ESMTP welcome
  QUIT

In this case, proxycheck's command line may look as follows:

  proxycheck -vv -d mail.example.com:25 \
   -c chat::"250 mail.example.com ESMTP welcome" list-of-IPs

Another usage scenario is to automatically submit all open proxies to DSBL.org-style blocklists. For this, specify -c dsbl and set up environment variables for dsbl client. The variables DSBL_USER and DSBL_PASS are required for non-anonymous DSBL submissions, for anonymous submissions to the unconfirmed.dsbl.org defaults are sufficient. To submit a proxy to DSBL.org, set destination to the mail exchanger of listme.dsbl.org domain, currently mx.listme.dsbl.org. For example:

  DSBL_USER=username DSBL_PASS=password ./proxycheck -vv \
   -dmx.listme.dsbl.org:25 -cdsbl proxyhost

Additional and updated information may be found at the URL below.

LICENSE

AUTHOR