Internet Trivial File Transfer Protocol proxy
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:
To make use of the proxy, pf.conf(5) needs
the following rules. The anchor is mandatory. Adjust the rule as needed for
tftp-proxy to use IPv4 addresses only.
tftp-proxy to use IPv6 addresses only.
- 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
options to specify both an IPv4 and an IPv6 address.
- 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.
- Listen on the specified address. By default
tftp-proxy listens on localhost addresses.
- Listen on the specified port. By default
tftp-proxy listens on port 6969.
- Log the connection and request information to
- Number of seconds to wait for the data transmission to begin before
removing the pf(4) rule. The default is 2
The current stand-alone implementation first appeared in
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