+
−.. -*- coding: utf-8; -*-
+
−
+
−===============
+
− Network port.
+
−===============
+
−.. contents::
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−   :local:
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−
+
−Port forwarding.
+
−================
+
−::
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−
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−  $ ssh -L 8888:www.linuxhorizon.ro:80 user@computer -N
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−  $ ssh -L 8888:www.linuxhorizon.ro:80 -L 110:mail.linuxhorizon.ro:110 \
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−    25:mail.linuxhorizon.ro:25 user@computer -N
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−
+
−The second example (see above) show you how to setup your ssh tunnel for web, pop3
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−and smtp. It is useful to recive/send your e-mails when you don't have direct access
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−to the mail server.
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−
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−For the ASCII art and lynx browser fans here is illustrated the first example::
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−
+
−   +----------+<--port 22-->+----------+<--port 80-->o-----------+
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−   |SSH Client|-------------|ssh_server|-------------|   host    |
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−   +----------+             +----------+             o-----------+
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−  localhost:8888              computer      www.linuxhorizon.ro:80
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−
+
−Reverse SSH Tunneling.
+
−======================
+
−
+
−Have you ever wanted to ssh to your Linux box that sits behind NAT? Now you can
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−with reverse SSH tunneling. This document will show you step by step how to set
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−up reverse SSH tunneling. The reverse SSH tunneling should work fine with Unix
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−like systems.
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−
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−Let's assume that Destination's IP is 192.168.20.55 (Linux box that you want to
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−access).
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−
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−You want to access from Linux client with IP 138.47.99.99.
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−Destination (192.168.20.55) <- NAT <- Source (138.47.99.99)
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−
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−SH from the destination to the source (with public ip) using command below::
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−
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−  $ ssh -R 19999:localhost:22 sourceuser@138.47.99.99
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−
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−port 19999 can be any unused port. Now you can SSH from source to destination
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−through SSH tuneling::
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−
+
−  $ ssh localhost -p 19999
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−
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−3rd party servers can also access 192.168.20.55 through Destination
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−(138.47.99.99). Destination::
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−
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−  (192.168.20.55) <- |NAT| <- Source (138.47.99.99) <- Bob's server
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−
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−From Bob's server::
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−
+
−  $ ssh sourceuser@138.47.99.99
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−
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−After the sucessful login to Source::
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−
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−  $ ssh localhost -p 19999
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−
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−The connection between destination and source must be alive at all time. Tip:
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−you may run a command (e.g. watch, top) on Destination to keep the connection
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−active.
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−
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−Port listening.
+
−===============
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−
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−Connect to a server::
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−
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−  $ nc hostname port
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−
+
−Be a server::
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−
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−  $ nc -l -p port
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−
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−Simple filetransfer.
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−====================
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−
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−Serve a file::
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−
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−  $ nc -l -p port < file
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−
+
−Receive a file::
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−
+
−  $ nc hostname port > file
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−
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−Filesystem cloning.
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−===================
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−
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−Serve the filesystem::
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−
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−  $ tar cOPp --same-owner / | nc -l -p port
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−
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−Receive the filesystem::
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−
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−  $ nc -w3 hostname port | tar xPp
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−
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−Disk cloning.
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−=============
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−
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−Serve the disk image::
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−
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−  $ dd if=/dev/hda | nc -l -p port
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−
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−Receive the image::
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−
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−  $ nc -w3 hostname port | dd of=/dev/hda
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−
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−Encrypted, compressed and IP restricted filetransfer.
+
−=====================================================
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−
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−If combining encryption and compression, be sure to compress first then
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−encrypt when sending and reverse the order for receiving. Do not attempt to
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−encrypt then compress. Compression works by finding patterns which are
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−destroyed intentionally by the process of encryption. Also, though not
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−required, specifying the IP address of the host that will be transferring the
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−file is a good idea.
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−
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−Serving a compresssed, encrypted file from 192.168.0.1 to 192.168.0.2::
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−
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−  $ gzip -c < file | openssl aes-128-cbc -e -k thispassword | nc -l 192.168.0.2 12345
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−
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−Receiving, decrypting and decompressing that file::
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−
+
−  $ nc 192.168.0.1 12345 | openssl aes-128-cbc -d -k thispassword | gunzip -c > file
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−
+
−Scan with nmap.
+
−===============
+
−::
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−
+
−  $ nmap HOSTNAME
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−
+
−Scan with netcat.
+
−=================
+
−::
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−
+
−  $ nc -v -w 2 -z hostname portrange
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−  $ nc -v -w 2 -z hostname portlisting
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−
+
−Where portrange is for example "10-20" to scan all ports between 10 and 20,
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−portlisting is for example 11,20,135 will scan these ports.
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−
+
−I just tried this on windows xp, and the comma separated list of ports does
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−NOT work. Instead, use space separated list. eg::
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−
+
−  cmd> nc.exe -vv -w 2 -z www.example.com 20-25 79 80 110 137-139 443
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−