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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