Cisco ASA 5505 - Manual (Page 544)

28-6
Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter 28 Configuring IPv6 Neighbor Discovery
Default Settings for IPv6 Neighbor Discovery
• The ICMP syslogs generated are caused by a regular refresh of IPv6 neighbor entries. The ASA
default timer for IPv6 neighbor entry is 30 seconds, so the ASA would generate ICMPv6 neighbor
discovery and response packets about every 30 seconds. If the ASA has both failover LAN and state
interfaces configured with IPv6 addresses, then every 30 seconds, ICMPv6 neighbor discovery and
response packets will be generated by both ASAs for both configured and link-local IPv6 addresses.
In addition, each packet will generate several syslogs (ICMP connection and local-host creation or
teardown), so it may appear that constant ICMP syslogs are being generated. The refresh time for
IPV6 neighbor entry is configurable on the regular data interface, but not configurable on the
failover interface. However, the CPU impact for this ICMP neighbor discovery traffic is minimal.
Default Settings for IPv6 Neighbor Discovery
Table 28-1 lists the default settings for IPv6 neighbor discovery.
Table 28-1 Default IPv6 Neighbor Discovery Parameters
Parameters Default
value for the neighbor solicitation transmission
message interval 1000 seconds between neighbor solicitation
transmissions.
value for the neighbor reachable time The default is 0.
value for the router advertisement transmission
interval The default is 200 seconds.
value for the router lifetime The default is 1800 seconds.
value for the number of consecutive neighbor
solicitation messages sent during DAD The default is one message.
prefix lifetime The default lifetime is 2592000 seconds (30 days),
and a preferred lifetime is 604800 seconds (7
days).
on-link flag The flag is on by default, which means that the
prefix is used on the advertising interface.
autoconfig flag The flag is on by default, which means that the
prefix is used for autoconfiguration.
static IPv6 neighbor Static entries are not configured in the IPv6
neighbor discovery cache.