sshuttle/docs/tproxy.rst
Scott Kuhl e11db3980f Minor improvement to tproxy documentation.
Previously, tproxy was unique in its support of IPv6. Now, many
sshuttle methods support IPv6 and tproxy remains the only option that
supports UDP.
2021-12-31 14:31:54 -05:00

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TPROXY
======
TPROXY is the only method that supports UDP.
There are some things you need to consider for TPROXY to work:
- The following commands need to be run first as root. This only needs to be
done once after booting up::
ip route add local default dev lo table 100
ip rule add fwmark {TMARK} lookup 100
ip -6 route add local default dev lo table 100
ip -6 rule add fwmark {TMARK} lookup 100
where {TMARK} is the identifier mark passed with -t or --tmark flag
as a hexadecimal string (default value is '0x01').
- The ``--auto-nets`` feature does not detect IPv6 routes automatically. Add IPv6
routes manually. e.g. by adding ``'::/0'`` to the end of the command line.
- The client needs to be run as root. e.g.::
sudo SSH_AUTH_SOCK="$SSH_AUTH_SOCK" $HOME/tree/sshuttle.tproxy/sshuttle --method=tproxy ...
- You may need to exclude the IP address of the server you are connecting to.
Otherwise sshuttle may attempt to intercept the ssh packets, which will not
work. Use the ``--exclude`` parameter for this.
- You need the ``--method=tproxy`` parameter, as above.
- The routes for the outgoing packets must already exist. For example, if your
connection does not have IPv6 support, no IPv6 routes will exist, IPv6
packets will not be generated and sshuttle cannot intercept them::
telnet -6 www.google.com 80
Trying 2404:6800:4001:805::1010...
telnet: Unable to connect to remote host: Network is unreachable
Add some dummy routes to external interfaces. Make sure they get removed
however after sshuttle exits.