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Michuelnik
Asked: 2012-12-19 00:00:08 +0800 CST

IPv6-"GARP"/ Gratuitous ND

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I am maintaining an office network with several VLANs. These VLANs are terminated by a redundant pair of Linux boxes as router. Between those I am running VRRP (with keepalived). On failure I am shifting my (virtual) gateway IPs between the two boxes. For IPv4 I am sending a bunch of GARPs afterwards to update the neighbour cache.

How should I proceed with IPv6? From the specs I would guess to do the same, just send an ND NA (with the S bit unset). Would that be right? If - what would be the preferred way for this? Unfortunately I was not able to find a tool like arping for GARP. Any Hints?

Thanks!

linux

1 Answers

  1. You shouldn't have to do anything special; I have exactly the same setup as you (multiple VLANs routed by a HA pair of Linux boxes using keepalived).

    I see keepalived sends Unsolicited NA's when a box takes MASTER:

    <snip>
Dec 18 12:03:29 fw1 Keepalived_vrrp[23646]: VRRP_Instance(ipv6) Sending Unsolicited Neighbour Adverts on bond0.11 for 2001:44b8:xxxx:xxxx::f0
Dec 18 12:03:29 fw1 Keepalived_vrrp[23646]: VRRP_Instance(ipv6) Sending Unsolicited Neighbour Adverts on bond0.12 for 2001:44b8:xxxx:xxxx::f0
Dec 18 12:03:29 fw1 Keepalived_vrrp[23646]: VRRP_Instance(ipv6) Sending Unsolicited Neighbour Adverts on bond0.14 for 2001:44b8:xxxx:xxxx::f0
Dec 18 12:03:29 fw1 Keepalived_vrrp[23646]: VRRP_Instance(ipv6) Sending Unsolicited Neighbour Adverts on bond0.15 for 2001:44b8:xxxx:xxxx::f0
Dec 18 12:03:29 fw1 Keepalived_vrrp[23646]: VRRP_Instance(ipv6) Sending Unsolicited Neighbour Adverts on bond0.16 for 2001:44b8:xxxx:xxxx::f0
Dec 18 12:03:29 fw1 Keepalived_vrrp[23646]: VRRP_Instance(ipv6) Sending Unsolicited Neighbour Adverts on bond0.18 for 2001:44b8:xxxx:xxxx::f0
Dec 18 12:03:29 fw1 Keepalived_vrrp[23646]: VRRP_Instance(ipv6) Sending Unsolicited Neighbour Adverts on bond0.19 for 2001:44b8:xxxx:xxxx::f0
<snip>
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