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.