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.Dd May 17, 1998
.Dt FAITHD 8
.Os
.Sh NAME
.Nm faithd
.Nd FAITH IPv6/v4 translator daemon
.Sh SYNOPSIS
.Nm
.Op Fl dp
.Op Ar service Op Ar serverpath Op Ar serverargs
.Sh DESCRIPTION
.Nm
provides IPv6/v4 TCP relay for the specified
.Ar service .
.Pp
.Nm
must be invoked on IPv4/v6 dual stack router.
The router must be configured to capture all the TCP traffic
toward reserved
.Tn IPv6
address prefix, by using
.Xr route 8
and
.Xr sysctl 8
commands.
.Nm
will daemonize itself on invocation.
.Pp
.Nm
will listen to
.Tn TCPv6
port
.Ar service .
If
.Tn TCPv6
traffic to port
.Ar service
is found,
.Nm
will relay the
.Tn TCPv6
traffic to
.Tn TCPv4 .
Destination for relayed
.Tn TCPv4
connection will be determined by the last 4 octets of the original
.Tn IPv6
destination.
For example, if
.Li 3ffe:0501:4819:ffff::
is reserved for
.Nm Ns ,
and the
.Tn TCPv6
destination address is
.Li 3ffe:0501:4819:ffff::0a01:0101 ,
the traffic will be relayed to IPv4 destination
.Li 10.1.1.1 .
.Pp
If
.Ar service
is not given,
.Li telnet
is assumed, and
.Nm
will relay TCP traffic on TCP port
.Li telnet .
With
.Ar service ,
.Nm
will work as TCP relaying daemon for specified
.Ar service
as described above.
.Pp
Since
.Nm
listens to TCP port
.Ar service ,
it is not possible to run local TCP daemons for port
.Ar service
on the router, using
.Xr inetd 8
or other standard mechanisms.
By specifying
.Ar serverpath
to
.Nm Ns ,
you can run local daemons on the router.
.Nm
will invoke local daemon at
.Ar serverpath
if the destination address is local interface address,
and will perform translation to IPv4 TCP in other cases.
You can also specify
.Ar serverargs
for the arguments for the local daemon.
.Pp
To use
.Nm
translation service,
an IPv6 address prefix must be reserved for mapping IPv4 addresses into.
Kernel must be properly configured to route all the TCP connection
toward the reserved IPv6 address prefix into the
.Dv faith
pseudo interface, by using
.Xr route 8
command.
Also,
.Xr sysctl 8
should be used to configure
.Dv net.inet6.ip6.keepfaith
to
.Dv 1 .
.Pp
If
.Fl d
is given, debugging information will be generated using
.Xr syslog 3 .
If
.Fl p
is given,
.Nm
will use privileged TCP port number as source port,
for IPv4 TCP connection toward final destination.
For relaying
.Xr ftp 1
and
.Xr rlogin 1 ,
.Fl p
is not necessary as special program code is supplied.
.Pp
.Nm
will relay both normal and out-of-band TCP data.
It is capable of emulating TCP half close as well.
.Nm
includes special support for protocols used by
.Xr ftp 1
and
.Xr rlogin 1 .
When translating FTP protocol,
.Nm
translates network level addresses in
.Li PORT/LPRT/EPRT
and
.Li PASV/LPSV/EPSV
commands.
For RLOGIN protocol,
.Nm
will relay back connection from
.Xr rlogind 8
on the server to
.Xr rlogin 1
on client.
.Pp
Inactive sessions will be disconnected in 30 minutes,
to avoid stale sessions from chewing up resources.
This may be inappropriate for some of the services
.Pq should this be configurable? .
.Sh EXAMPLES
Before invoking
.Nm Ns ,
.Xr faith 4
interface has to be configured properly.
.Pp
To translate
.Li telnet
service, and provide no local telnet service, invoke
.Nm
as either of the following:
.Bd -literal -offset
# faithd
# faithd telnet
.Ed
.Pp
If you would like to provide local telnet service via
.Xr telnetd 8
on
.Pa /usr/libexec/telnetd ,
user the following command line:
.Bd -literal -offset
# faithd telnet /usr/libexec/telnetd telnetd
.Ed
.Pp
If you would like to pass extra arguments to the local daemon:
.Bd -literal -offset
# faithd ftpd /usr/libexec/ftpd ftpd -l
.Ed
.Pp
Here are some other examples:
.Bd -literal -offset
# faithd sshd
# faithd login /usr/libexec/rlogin rlogind
# faithd shell /usr/libexec/rshd rshd
.Ed
.Pp
However, you should be careful when translating rlogin or rsh
connections. See
.Sx SECURITY NOTICE
for more details.
.Sh RETURN VALUES
.Nm
exits with
.Dv EXIT_SUCCESS
.Pq 0
on success, and
.Dv EXIT_FAILURE
.Pq 1
on error.
.Sh SEE ALSO
.Xr faith 4 ,
.Xr route 8 ,
.Xr sysctl 8
.Rs
.%A Jun-ichiro itojun Hagino
.%A Kazu Yamamoto
.%T "An IPv6-to-IPv4 transport relay translator"
.%R internet draft
.%N draft-ietf-ngtrans-tcpudp-relay-01.txt
.%O work in progress material
.Re
.Sh SECURITY NOTICE
It is very insecure to use
.Xr rhosts 5
and other IP-address based authentication, for connections relayed by
.Nm
.Pq and any other TCP relaying services .
.Pp
.Nm
itself does not implement access controls, as
it intends to implement transparent TCP relay services.
Administrators are advised to filter packets based on IPv6 address.
IPv6 destination address can be limited by
carefully configuring routing entries that points to
.Xr faith 4 ,
using
.Xr route 8 .
IPv6 source address needs to be filtered by using packet filters.
Documents listed in
.Sx SEE ALSO
have more discussions on this topic.
.\"
.Sh HISTORY
The
.Nm
command first appeared in WIDE Hydrangea IPv6 protocol stack kit.