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30 .\" $FreeBSD: src/usr.sbin/faithd/faithd.8,v 1.2.2.12 2003/03/12 22:08:14 trhodes Exp $
37 .Nd FAITH IPv6/v4 translator daemon
41 .Op Fl f Ar configfile
43 .Op Ar serverpath Op Ar serverargs
47 utility provides IPv6-to-IPv4 TCP relay. It
48 must be used on an IPv4/v6 dual stack router.
60 Destination for relayed
62 connection will be determined by the last 4 octets of the original
66 .Li 2001:db8:4819:ffff::
71 destination address is
72 .Li 2001:db8:4819:ffff::a01:101 ,
73 the traffic will be relayed to IPv4 destination
79 an IPv6 address prefix must be reserved for mapping IPv4 addresses into.
80 Kernel must be properly configured to route all the TCP connection
81 toward the reserved IPv6 address prefix into the
83 pseudo interface, by using
88 should be used to configure
89 .Va net.inet6.ip6.keepfaith
93 The router must be configured to capture all the TCP traffic
96 address prefix, by using
104 utility needs a special name-to-address translation logic, so that
105 hostnames gets resolved into special
108 For small-scale installation, use
110 For large-scale installation, it is useful to have
111 a DNS server with special address translation support.
112 An implementation called
116 .Pa http://www.vermicelli.pasta.cs.uit.no/software/totd.html
117 Make sure you do not propagate translated DNS records to normal DNS cloud,
118 it is highly harmful.
122 is invoked as a standalone program,
124 will daemonize itself.
127 utility will listen to
135 is found, it relays the connection.
141 it is not possible to run local TCP daemons for port
145 or other standard mechanisms.
150 you can run local daemons on the router.
153 utility will invoke local daemon at
155 if the destination address is local interface address,
156 and will perform translation to IPv4 TCP in other cases.
159 for the arguments for the local daemon.
161 The following options are available:
162 .Bl -tag -width indent
164 Debugging information will be generated using
166 .It Fl f Ar configfile
167 Specify a configuration file for access control.
170 Use privileged TCP port number as source port,
171 for IPv4 TCP connection toward final destination.
176 this flag is not necessary as special program code is supplied.
181 utility will relay both normal and out-of-band TCP data.
182 It is capable of emulating TCP half close as well.
185 utility includes special support for protocols used by
189 When translating FTP protocol,
191 translates network level addresses in
198 will relay back connection from
204 Inactive sessions will be disconnected in 30 minutes,
205 to avoid stale sessions from chewing up resources.
206 This may be inappropriate for some of the services
207 (should this be configurable?).
214 will handle connection passed from standard input.
215 If the connection endpoint is in the reserved IPv6 address prefix,
217 will relay the connection.
220 will invoke service-specific daemon like
222 by using the command argument passed from
227 utility determines operation mode by the local TCP port number,
228 and enables special protocol handling whenever necessary/possible.
233 on FTP port, it will operate as a FTP relay.
235 The operation mode requires special support for
240 To prevent malicious accesses,
242 implements a simple address-based access control.
250 will avoid relaying unwanted traffic.
253 contains directives with the following format:
256 .Ar src Ns / Ns Ar slen Cm deny Ar dst Ns / Ns Ar dlen
258 If the source address of a query matches
259 .Ar src Ns / Ns Ar slen ,
260 and the translated destination address matches
261 .Ar dst Ns / Ns Ar dlen ,
264 .Ar src Ns / Ns Ar slen Cm permit Ar dst Ns / Ns Ar dlen
266 If the source address of a query matches
267 .Ar src Ns / Ns Ar slen ,
268 and the translated destination address matches
269 .Ar dst Ns / Ns Ar dlen ,
270 permit the connection.
273 The directives are evaluated in sequence,
274 and the first matching entry will be effective.
276 (if we reach the end of the ruleset)
277 the traffic will be denied.
280 traffic may be filtered by using access control functionality in
296 interface has to be configured properly.
298 # sysctl net.inet6.ip6.accept_rtadv=0
299 # sysctl net.inet6.ip6.forwarding=1
300 # sysctl net.inet6.ip6.keepfaith=1
302 # route add -inet6 2001:db8:4819:ffff:: -prefixlen 96 ::1
303 # route change -inet6 2001:db8:4819:ffff:: -prefixlen 96 -ifp faith0
305 .Ss Daemon mode samples
308 service, and provide no local telnet service, invoke
315 If you would like to provide local telnet service via
318 .Pa /usr/libexec/telnetd ,
319 use the following command line:
321 # faithd telnet /usr/libexec/telnetd telnetd
324 If you would like to pass extra arguments to the local daemon:
326 # faithd ftp /usr/libexec/ftpd ftpd -l
329 Here are some other examples.
332 to translate rsh/rlogin services.
335 # faithd login /usr/libexec/rlogin rlogind
336 # faithd shell /usr/libexec/rshd rshd
339 However, you should be careful when translating rlogin or rsh
342 .Sx SECURITY CONSIDERATIONS
344 .Ss inetd mode samples
345 Add the following lines into
347 Syntax may vary depending upon your operating system.
349 telnet stream tcp6/faith nowait root /usr/sbin/faithd telnetd
350 ftp stream tcp6/faith nowait root /usr/sbin/faithd ftpd -l
351 ssh stream tcp6/faith nowait root /usr/sbin/faithd /usr/sbin/sshd -i
355 will open listening sockets with enabling kernel TCP relay support.
356 Whenever connection comes in,
360 If it the connection endpoint is in the reserved IPv6 address prefix.
363 utility will relay the connection.
366 will invoke service-specific daemon like
368 .Ss Access control samples
369 The following illustrates a simple
373 # permit anyone from 2001:db8:ffff::/48 to use the translator,
374 # to connect to the following IPv4 destinations:
375 # - any location except 10.0.0.0/8 and 127.0.0.0/8.
376 # Permit no other connections.
378 2001:db8:ffff::/48 deny 10.0.0.0/8
379 2001:db8:ffff::/48 deny 127.0.0.0/8
380 2001:db8:ffff::/48 permit 0.0.0.0/0
387 .%A Jun-ichiro itojun Hagino
389 .%T "An IPv6-to-IPv4 transport relay translator"
391 .%O ftp://ftp.isi.edu/in-notes/rfc3142.txt
398 utility first appeared in WIDE Hydrangea IPv6 protocol stack kit.
401 IPv6 and IPsec support based on the KAME Project
402 .Pa ( http://www.kame.net/ )
403 stack was initially integrated into
405 .Sh SECURITY CONSIDERATIONS
406 It is very insecure to use
408 and other IP-address based authentication, for connections relayed by
410 (and any other TCP relaying services).
412 Administrators are advised to limit accesses to
416 or by using IPv6 packet filters.
419 service from malicious parties and avoid theft of service/bandwidth.
420 IPv6 destination address can be limited by
421 carefully configuring routing entries that points to
425 IPv6 source address needs to be filtered by using packet filters.
428 have more discussions on this topic.