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proxytunnel(1)

NAME

proxytunnel - program to tunnel a connection through a standard HTTPS proxy

SYNOPSIS

proxytunnel [OPTION…] [host:port]

DESCRIPTION

proxytunnel is a program to tunnel any connection through a standard HTTPS proxy, circumventing standard HTTP filtering mechanisms. It’s mostly used as a backend for OpenSSH’s ProxyCommand, and as a proxy backend for Putty. It can also be used for other proxy-traversing purposes like proxy bouncing.

OPTIONS

-i, --inetd

Run from inetd (default: off).

-a, --standalone=[address:]port

Run as standalone daemon on specified address and port. address may be a IPv4 address, a bracket-enclosed IPv6 address or a bracket-enclosed combination of IPv6 address, \'%' and interface name. The latter format is only required with link-local IPv6 addresses. The daemon listens on any address if address is not given.

Examples

22, 123.45.67.89:22, [2001:db8::123:4567:89ab:cdef]:22, [2001:db8::123:4567:89ab:cdef%eth0]:22

-p, --proxy=host:port

Use host and port as the local proxy to connect to, if not specified the HTTP_PROXY environment variable, if set, will be used instead.

-r, --remproxy=host:port

Use host and port as the remote (secondary) proxy to connect to.

-d, --dest=host:port

Use host and port as the destination for the tunnel, you can also specify them as the argument to the proxytunnel command.

-e, --encrypt

SSL encrypt data between local proxy and destination.

-E, --encrypt-proxy

SSL encrypt data between client and local proxy.

-X, --encrypt-remproxy

SSL encrypt data between local and remote (secondary) proxy.

ADDITIONAL OPTIONS

-W, --wa-bug-29744

Workaround ASF Bugzilla 29744: If SSL is in use (by -e, -E, -X options), stop using it immediately after the CONNECT exchange to workaround apache server bugs (This might not work on all setups).

-B, --buggy-encrypt-proxy

Equivalent to -E -W (Provided for backwards compatibility).

-L, --tlsenforce

Enforce TLSv1 connection (legacy).

-T, --no-ssl3

Prevent the use of SSLv3 in encrypted connections (default: enabled).

-z, --no-check-certificate

Do not verify server SSL certificate when establishing an SSL connection. By default, the server SSL certificate is verified and the target host name is checked against the server certificate’s subject alternative names if any are present, or common name if there are no subject alternative names.

-C, --cacert=filename/directory

Specify a CA certificate file (or directory containing CA certificate(s)) to trust when verifying a server SSL certificate. If a directory is provided, it must be prepared with OpenSSL’s c_rehash tool (default, unless changed at compile time using DEFAULT_CA_FILE or DEFAULT_CA_DIR options: /etc/ssl/certs).

-4, --ipv4

Enforce the use of IPv4 when connecting to the local proxy.

-6, --ipv6

Enforce the use of IPv6 when connecting to the local proxy.

-F, --passfile=filename

Use filename for reading username and password for HTTPS proxy authentication, the file uses the same format as .wgetrc and can be shared with wget. Use this option, or environment variables to hide the password from other users.

-P, --proxyauth=username:password

Use username and password as credentials to authenticate against a local HTTPS proxy, the username and password can also be specified in the PROXYUSER and PROXYPASS environment variables to hide them from other users. If the password is omitted and no PROXYPASS environment variable is set, proxytunnel will prompt for a password.

-R, --remproxyauth=username:password

Use username and password as credentials to authenticate against a remote (secondary) HTTPS proxy, the username and password can also be specified in the REMPROXYUSER and REMPROXYPASS environment variables to hide them from other users. If the password is omitted and no REMPROXYPASS environment variable is set, proxytunnel will prompt for a password.

-c, --cert=filename

Provide the name of the file containing the SSL client certificate to authenticate by client certificate against local proxy, remote proxy or destination. The file must be in PEM format. On top of this it may contain one or more intermediary certificates missing at the servers’s end, effectively forming a certificate chain. Requires specification of -k, --key in addition. Ignored if neither -e, --encrypt nor -E, --encrypt-proxy nor -X, --encrypt-remproxy is given.

-k, --key=filename

Provide the name of the file containing the SSL client key to authenticate by client certificate against local proxy, remote proxy or destination. The file must be in PEM format. Requires specification of -c, --cert in addition. Ignored if neither -e, --encrypt nor -E, --encrypt-proxy nor -X, --encrypt-remproxy is given.

-N, --ntlm

Use NTLM based authentication.

-t, --domain=STRING

Specify NTLM domain (default: autodetect).

-H, --header=STRING

Add additional HTTP headers to send to proxy.

-o, --host=host[:port]

Send a custom Host header. With SSL connections host is also sent as SNI.

-x, --proctitle=STRING

Use a different process title.

MISCELLANEOUS OPTIONS

-v, --verbose

Turn on verbosity.

-q, --quiet

Suppress messages.

-h, --help

Print help and exit.

-V, --version

Print version and exit.

ARGUMENTS

host:port is the destination hostname and port number combination.

Note
 Specifying the destination as arguments is exactly the same as specifying them using the -d or --dest option.

USAGE

Depending on your situation you might want to do any of the following things:

  • Connect through a local proxy to your home system on port 22

    $ proxytunnel -v -p proxy.company.com:8080 -d system.home.nl:22

  • Connect through a local proxy (with authentication) to your home system

    $ proxytunnel -v -p proxy.company.com:8080 -P username:password -d system.home.nl:22

  • Connect through a local proxy (with authentication) hiding your password

    $ export PROXYPASS=password
$ proxytunnel -v -p proxy.company.com:8080 -P username -d system.home.nl:22

  • Connect through a local proxy to a remote proxy and bounce to any system

    $ proxytunnel -v -p proxy.company.com:8080 -r proxy.athome.nl:443 -d system.friend.nl:22

  • Connect using SSL through a local proxy to your home system

    $ proxytunnel -v -E -p proxy.company.com:8080 -d system.home.nl:22

OPENSSH CONFIGURATION

To use this program with OpenSSH to connect to a host somewhere, create a ~/.ssh/config file with the following content:

Host system.athome.nl
    ProxyCommand proxytunnel -p proxy.company.com:8080 -d %h:%p
    ServerAliveInterval 30
Note
 The ServerAliveInterval directive makes sure that idle connections are not being dropped by intermediate firewalls that remove active sessions aggressively. If you see your connection dropping out, try to lower the value even more.

To use the dynamic (SOCKS) portforwarding capability of the SSH client, you can specify the DynamicForward directive in your ssh_config file like:

Host system.athome.nl
    DynamicForward 1080
    ProxyCommand proxytunnel -p proxy.company.com:8080 -d %h:%p
    ServerAliveInterval 30

NOTES

Important
 Most HTTPS proxies do not allow access to ports other than HTTPS (tcp/443) and SNEWS (tcp/563). In this case you need to make sure the SSH daemon or remote proxy on the destination system is listening on either tcp/443 or tcp/563 to get through.

ENVIRONMENT

Proxytunnel can be influenced by setting one of the following environment variables:

HTTP_PROXY

If this environment variable is set, proxytunnel will use it as the local proxy if -p or --proxy is not provided.

PROXYUSER

If this environment variable is set, proxytunnel will use it as the username for proxy authentication, unless specified using the -P or --proxyauth option.

PROXYPASS

If this environment variable is set, proxytunnel will use it as the password for proxy authentication, unless specified using the -P or --proxyauth option.

REMPROXYUSER

If this environment variable is set, proxytunnel will use it as the username for remote (secondary) proxy authentication, unless specified using the -R or --remproxyauth option.

REMPROXYPASS

If this environment variable is set, proxytunnel will use it as the password for remote (secondary) proxy authentication, unless specified using the -R or --remproxyauth option.

SEE ALSO

ssh(1), ssh_config(8)

BUGS

This software is bug-free, at least we’d like to think so. If you do not agree with us, please provide the proof with your friendly report at https://github.com/proxytunnel/proxytunnel/issues :)

AUTHOR

This manpage was initially written by Loïc Le Guyader <[email protected]> for the Debian GNU/Linux system, revamped in asciidoc by Dag Wieërs <[email protected]> and is now maintained by the Proxytunnel developers.