NAME¶
dns2tcpc - A tunneling tool that encapsulate TCP traffic over DNS.
SYNOPSIS¶
dns2tcpc [
-h ] [
-c ] [
-z domain zone ] [
-d debug_level ] [
-r resource ] [
-k
key ] [
-f config_file ] [
-e command ] [
-T request type ] [
-l local_port ] [
server ]
DESCRIPTION¶
dns2tcpc is a network tool used to encapsulate TCP communications in DNS. When
connections are received on a specific port all TCP traffic is sent to the
remote dns2tcpd server and forwarded to a specific host and port. Multiple
connections are supported.
dns2tcpc was written for demonstration purposes.
OPTIONS¶
- -h
- Help Menu
- -c
- Enable DNS compression. When used, be sure that all relay
and DNS server support compression and really use it.
- -z domain zone
- Use this domain as endpoint.
- -d debug level
- Change debug level. Levels available are 1, 2 or 3.
- -r resource
- Remote resource to access.
- -k key
- Pre shared key used for authentication
(identification).
- -f config file
- Configuration file to use.
- -T request type
- Request type to use. Actually only KEY and TXT requests are
supported.
- -e command
- Command to execute, I/O are redirected in the tunnel.
- -l local_port
- Local port accepting incomming connections (or - for stdin
on UNIX systems).
- -t connection timeout
- Maximum DNS server's answer delay in seconds. A valid delay
is between 1 and 240 seconds. Default is 3.
- server
- DNS server to use. The first entry in resolv.conf file will
be choosen if the server is not specified.
CONFIGURATION FILES¶
By default ${HOME}/.dns2tcprc is used if no configuration file is specified.
Here is an example :
-
- domain = dns2tcp.hsc.fr resource = ssltunnel local_port =
4430 enable_compression = 0 debug_level = 1 key = mykey # DNS to use
server = ns.hsc.fr
EXAMPLES¶
- dns2tcpc -k mykey -z dns2tcp.hsc.fr
mydns
- Ask the dns2tcp server to list available resources.
- ssh -o 'ProxyCommand dns2tcpc -r ssh -l - -z
dns2tcp.hsc.fr -k mykey mydns' myserver
- Use dns2tcp as a proxy command with ssh. We try to connect
to the ssh resource with the key 'mykey' and the DNS mydns.
- dns2tcpc -r socat-resource -e '/bin/bash -i' -k
mykey -z dns2tcp.hsc.fr mydns
- Use dns2tcp as a reverse shell, the remote shell will
appear on the socat-resource.
- dns2tcpc -d 1 -f /dev/null -r ssl-tunnel -l 2000 -k
mykey -T KEY -z dns2tcp.hsc.fr mydns
- Do not use the default configuration file, bind local port
2000 and forward all the traffic on the remote ssl-tunnel resource, use
the first debug level. Use KEY type DNS requests.
AUTHORS¶
Olivier Dembour <olivier.dembour@hsc.fr>
SEE ALSO¶
ssltunnel
