FAITHD(8)               OpenBSD System Manager's Manual              FAITHD(8)

NAME
     faithd - FAITH IPv6/v4 translator daemon

SYNOPSIS
     faithd [-dp] [-f configfile] service [serverpath [serverargs]]

DESCRIPTION
     faithd provides IPv6-to-IPv4 TCP relay.  faithd must be used on an
     IPv4/v6 dual stack router.

     When faithd receives TCPv6 traffic, faithd will relay the TCPv6 traffic
     to TCPv4. Destination for relayed TCPv4 connection will be determined by
     the last 4 octets of the original IPv6 destination.  For example, if
     3ffe:0501:4819:ffff:: is reserved for faithd, and the TCPv6 destination
     address is 3ffe:0501:4819:ffff::0a01:0101, the traffic will be relayed to
     IPv4 destination 10.1.1.1.

     To use faithd translation service, an IPv6 address prefix must be re-
     served for mapping IPv4 addresses into.  Kernel must be properly config-
     ured to route all the TCP connection toward the reserved IPv6 address
     prefix into the faith(4) pseudo interface, by using route(8) command.
     Also, sysctl(8) should be used to configure net.inet6.ip6.keepfaith to 1.

     The router must be configured to capture all the TCP traffic toward re-
     served IPv6 address prefix, by using route(8) and sysctl(8) commands.

     faithd needs a special name-to-address translation logic, so that host-
     names gets resolved into special IPv6 address prefix.  For small-scale
     installation, use hosts(5). For large-scale installation, it is useful to
     have a DNS server with special address translation support.  An implemen-
     tation called totd is available at
     http://www.vermicelli.pasta.cs.uit.no/ipv6/software.html. Make sure you
     do not propagate translated DNS records to normal DNS cloud, it is highly
     harmful.

     When faithd is invoked, faithd will daemonize itself.  faithd will listen
     to TCPv6 port service. If TCPv6 traffic to port service is found, it re-
     lays the connection.

     Since faithd listens to TCP port service, it is not possible to run local
     TCP daemons for port service on the router, using inetd(8) or other stan-
     dard mechanisms.  By specifying serverpath to faithd, you can run local
     daemons on the router.  faithd will invoke local daemon at serverpath if
     the destination address is local interface address, and will perform
     translation to IPv4 TCP in other cases.  You can also specify serverargs
     for the arguments for the local daemon.

     The following options are available:

     -d      Debugging information will be generated using syslog(3).

     -f configfile
             Specify a configuration file for access control.  See below.

     -p      Use privileged TCP port number as source port, for IPv4 TCP con-
             nection toward final destination.  For relaying ftp(1) and
             rlogin(1), this flag is not necessary as special program code is
             supplied.

     faithd will relay both normal and out-of-band TCP data.  It is capable of
     emulating TCP half close as well.  faithd includes special support for
     protocols used by ftp(1) and rlogin(1). When translating FTP protocol,
     faithd translates network level addresses in PORT/LPRT/EPRT and
     PASV/LPSV/EPSV commands.  For RLOGIN protocol, faithd will relay back
     connection from rlogind(8) on the server to rlogin(1) on client.

     Inactive sessions will be disconnected in 30 minutes, to avoid stale ses-
     sions from chewing up resources.  This may be inappropriate for some of
     the services (should this be configurable?).

   Access control
     To prevent malicious accesses, faithd implements a simple address-based
     access control.  With /etc/faithd.conf (or configfile specified by -f),
     faithd will avoid relaying unwanted traffic.  The faithd.conf contains
     directives with the following format:

     o   src/slen deny dst/dlen

         If the source address of a query matches src/slen, and the translated
         destination address matches dst/dlen, deny the connection.

     o   src/slen permit dst/dlen

         If the source address of a query matches src/slen, and the translated
         destination address matches dst/dlen, permit the connection.

     The directives are evaluated in sequence, and the first matching entry
     will be effective.

EXAMPLES
     Before invoking faithd, faith(4) interface has to be configured properly.

     # sysctl -w net.inet6.ip6.accept_rtadv=0
     # sysctl -w net.inet6.ip6.forwarding=1
     # sysctl -w net.inet6.ip6.keepfaith=1
     # ifconfig faith0 up
     # route add -inet6 3ffe:501:4819:ffff:: -prefixlen 96 ::1
     # route change -inet6 3ffe:501:4819:ffff:: -prefixlen 96 -ifp faith0

     To translate telnet service, and provide no local telnet service, invoke
     faithd as follows:

     # faithd telnet

     If you would like to provide local telnet service via telnetd(8) on
     /usr/libexec/telnetd, use the following command line:

     # faithd telnet /usr/libexec/telnetd telnetd

     If you would like to pass extra arguments to the local daemon:

     # faithd ftp /usr/libexec/ftpd ftpd -l

     Here are some other examples.  You may need -p to translate rsh/rlogin
     services.

     # faithd ssh
     # faithd login /usr/libexec/rlogin rlogind
     # faithd shell /usr/libexec/rshd rshd

     However, you should be careful when translating rlogin or rsh connec-
     tions.  See SECURITY CONSIDERATIONS for more details.

   Access control samples
     The following illustrates a simple faithd.conf setting.

     # permit anyone from 3ffe:501:ffff::/48 to use the translator,
     # to connect to the following IPv4 destinations:
     # - any location except 10.0.0.0/8 and 127.0.0.0/8.
     # Permit no other connections.
     #
     3ffe:501:ffff::/48 deny 10.0.0.0/8
     3ffe:501:ffff::/48 deny 127.0.0.0/8
     3ffe:501:ffff::/48 permit 0.0.0.0/0

RETURN VALUES
     faithd exits with EXIT_SUCCESS (0) on success, and EXIT_FAILURE (1) on
     error.

SEE ALSO
     faith(4), route(8), sysctl(8)

     Jun-ichiro itojun Hagino, and Kazu Yamamoto, An IPv6-to-IPv4 transport
     relay translator, internet draft, draft-ietf-ngtrans-tcpudp-relay-04.txt,
     work in progress material.

HISTORY
     The faithd command first appeared in WIDE Hydrangea IPv6 protocol stack
     kit.

SECURITY CONSIDERATIONS
     It is very insecure to use rhosts(5) and other IP-address based authenti-
     cation, for connections relayed by faithd (and any other TCP relaying
     services).

     Administrators are advised to limit accesses to faithd using faithd.conf,
     or by using IPv6 packet filters.  It is to protect faithd service from
     malicious parties and avoid theft of service/bandwidth.  IPv6 destination
     address can be limited by carefully configuring routing entries that
     points to faith(4), using route(8). IPv6 source address needs to be fil-
     tered by using packet filters.  Documents listed in SEE ALSO have more
     discussions on this topic.

OpenBSD 2.9                      May 17, 1998                                3
