Re: Disable auto_linklocal
On Sun, Jan 15, 2012 at 7:27 AM, Freek Dijkstra pub...@macfreek.nl wrote: The link-local addresses don't really harm, but I found them confusing, as the host is running as a router, and rtadv announces the link-local address by default. IPv6-standards-wise, this is the correct thing to do. Router advertisements should contain link-local source addresses and advertise the link-local address as the router; the globally-routable prefix that is being advertised is a completely different field in those messages. I'm not too sure of the reasons behind this, other than eliminating some need for carp(4): you can have multiple routers on a subnet and if one goes down, clients will just pick up the other's router advertisements. It's atypical that one would want to disable link-local addressing, since it's one of the core differences from IPv4 that adds some benefit and flexibility. References: http://tools.ietf.org/html/rfc4861#section-4.2 Source Address MUST be the link-local address assigned to the interface from which this message is sent. -- Matt Mullins ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: Disable auto_linklocal
Matt Mullins wrote: The link-local addresses don't really harm, but I found them confusing, as the host is running as a router, and rtadv announces the link-local address by default. IPv6-standards-wise, this is the correct thing to do. Router advertisements should contain link-local source addresses and advertise the link-local address as the router; the globally-routable prefix that is being advertised is a completely different field in those messages. Hi Matt, Thanks for the info. I figured out as much. It is not possible to turn of link-local addresses in FreeBSD 9. Neither sysctl net.inet6.ip6.auto_linklocal=0 nor ifconfig em0 inet6 -auto_linklocal has any effect. The man page for ifconfig explicitly states that removing the link-local IPv6 address may result in unexpected behaviour The good news is that it *is* possible to use the global scope IPv6 address in router advertisements. RFC 4861, as you mentioned, defines a prefix. However, RFC 6275 alters the property of that field if a new flag, the router address flag, is set. In that case, the prefix field can contain the actual IPv6 address of the router. Apparently, this is needed for mobile IP. Unfortunately rtadvd (the default BSD router advertisement daemon) does not support this R-flag. The radvd daemon (available in a port) does support this bit by setting: AdvRouterAddr on Wireshark show that indeed this works. Unfortunately, most of my clients on the network still don't understand this bit, so it seems that after all I just have to remember the link-local IP addresses next to the global scope IP addresses for my network. Oh well, they say it's good to train one's memory :) Freek ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Disable auto_linklocal
Hello, I like to disable linklocal IPv6 addresses on my host, running FreeBSD 9.0-RC3. I already set net.inet6.ip6.auto_linklocal in /etc/sysctl.conf. # sysctl net.inet6.ip6.auto_linklocal net.inet6.ip6.auto_linklocal: 0 Even after a reboot, this does not seem to have any effect. Here is the config on one interface: % ifconfig em3 em3: flags=8843UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST metric 0 mtu 1500 options=219bRXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM, TSO4,WOL_MAGIC ether 00:00:24:ce:69:ef inet 172.25.129.1 netmask 0xff00 broadcast 172.25.129.255 inet6 fe80::200:24ff:fece:69ef%em3 prefixlen 64 scopeid 0xc inet6 2001:610::::1 prefixlen 64 nd6 options=21PERFORMNUD,AUTO_LINKLOCAL media: Ethernet autoselect (1000baseT full-duplex) status: active Did I overlook something? Is there perhaps a per-interface option I need to configure in /etc/rc.conf? The link-local addresses don't really harm, but I found them confusing, as the host is running as a router, and rtadv announces the link-local address by default. Thanks for any help, Freek ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
