Date: Thu, 28 Apr 2011 16:55:21 +1000 (EST) From: Mark Andrews <marka@isc.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: docs/156689: stf output-only documentation gives bad configuration advice Message-ID: <201104280655.p3S6tLmL013440@sex.dv.isc.org> Resent-Message-ID: <201104280700.p3S70MaA018728@freefall.freebsd.org>
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>Number: 156689 >Category: docs >Synopsis: stf output-only documentation gives bad configuration advice >Confidential: no >Severity: non-critical >Priority: high >Responsible: freebsd-doc >State: open >Quarter: >Keywords: >Date-Required: >Class: doc-bug >Submitter-Id: current-users >Arrival-Date: Thu Apr 28 07:00:21 UTC 2011 >Closed-Date: >Last-Modified: >Originator: Mark Andrews >Release: FreeBSD 8.2-STABLE i386 >Organization: ISC >Environment: System: FreeBSD sex.dv.isc.org 8.2-STABLE FreeBSD 8.2-STABLE #10: Sat Feb 26 18:02:12 EST 2011 marka@sex.dv.isc.org:/usr/obj/usr/src/sys/DEBUG i386 >Description: The stf documentation suggests the following configuration. This will result in traffic originating from the 6to4 address for which reply traffic will not be accepted. # ifconfig ne0 inet 133.4.5.6 netmask 0xffffff00 # ifconfig stf0 inet6 2002:8504:0506:0000:a00:5aff:fe38:6f86 \ prefixlen 16 alias deprecated link0 # route add -inet6 2002:: -prefixlen 16 ::1 # route change -inet6 2002:: -prefixlen 16 ::1 -ifp stf0 >How-To-Repeat: Configure the system as above and try to talk to any a machine with a 6to4 address. You can observe the traffic with tcpdump. e.g. "tcpdump -i ne0 -n -p not udp and not tcp and not arp" will remove most of the extranious packets. >Fix: Use "anycast" rather than "deprecated" so that the kernel will choose a different IPv6 source address. # ifconfig ne0 inet 133.4.5.6 netmask 0xffffff00 # ifconfig stf0 inet6 2002:8504:0506:: prefixlen 16 alias anycast link0 # route add -inet6 2002:: -prefixlen 16 ::1 # route change -inet6 2002:: -prefixlen 16 ::1 -ifp stf0 I tested this on a FreeBSD 4.11 box but I don't believe this part of the stack has changed much since then. The above documentation is from FreeBSD 8. >Release-Note: >Audit-Trail: >Unformatted:
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