TFTP-PROXY(8) | System Manager's Manual | TFTP-PROXY(8)

# NAME

`tftp-proxy` — Internet Trivial File Transfer Protocol proxy

# SYNOPSIS

`tftp-proxy` | [`-46dv`] [`-a` address] [`-l` address] [`-p` port] [`-w` transwait]

# DESCRIPTION

`tftp-proxy` is a proxy for the Internet Trivial File Transfer Protocol. TFTP connections should be redirected to the proxy using a pf(4) rule using the divert-to option, after which the proxy connects to the server on behalf of the client. The connection from the proxy to the server needs to be passed by a rule with divert-reply set.

The proxy inserts pf(4) pass and/or rdr rules using the anchor facility to allow payload packets between the client and the server. Once the rules are inserted, `tftp-proxy` forwards the initial request from the client to the server to begin the transfer. After transwait seconds, the states are assumed to have been established and the pf(4) rules are deleted and the program exits. Once the transfer between the client and the server is completed, the states will naturally expire.

The options are as follows:

`-4`
  Forces `tftp-proxy` to use IPv4 addresses only.
`-6`
  Forces `tftp-proxy` to use IPv6 addresses only.
`-a` address
  The proxy will use address as the source address for the initial request from the client to the server for NAT traversal. Instead of a “pass in” rule an “rdr” rule will be generated. It is possible to have two `-a` options to specify both an IPv4 and an IPv6 address.
`-d`
  Do not daemonize. If this option is specified, `tftp-proxy` will run in the foreground and log the client IP, type of request, and filename to stderr.
`-l` address
  Listen on the specified address. By default `tftp-proxy` listens on localhost addresses.
`-p` port
  Listen on the specified port. By default `tftp-proxy` listens on port 6969.
`-v`
  Log the connection and request information to syslogd(8).
`-w` transwait
  Number of seconds to wait for the data transmission to begin before removing the pf(4) rule. The default is 2 seconds.

# CONFIGURATION

To make use of the proxy, pf.conf(5) needs the following rules. The anchor is mandatory. Adjust the rule as needed for your configuration.

    anchor "tftp-proxy/*"
    pass in quick on $int_if inet proto udp from $lan to port tftp \
        divert-to 127.0.0.1 port 6969
    pass out quick on $ext_if inet proto udp from $lan to port tftp \
        group _tftp_proxy divert-reply

# SEE ALSO

tftp(1), pf(4), pf.conf(5), ftp-proxy(8), syslogd(8), tftpd(8)

# HISTORY

The current stand-alone implementation first appeared in OpenBSD 5.3.

# AUTHORS

David Gwynne <dlg@openbsd.org>

March 31, 2022 | Debian