ECS4110-52P_Management Guide

C HAPTER 46 | IP Interface Commands
Neighbor Discovery
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COMMAND MODE
Interface Configuration (Ethernet, Port Channel)
COMMAND USAGE
◆ IPv6 Router Advertisements (RA) convey information that enables
nodes to auto-configure on the network. This information may include
the default router address taken from the observed source address of
the RA message, as well as on-link prefix information. However,
unintended misconfigurations, or possibly malicious attacks on the
network, may lead to bogus RAs being sent, which in turn can cause
operational problems for hosts on the network.
◆ This command can be used to block RAs and Router Redirect (RR)
messages on the specified interface. Determine which interfaces are
connected to known routers, and enable RA Guard on all other
untrusted interfaces.
EXAMPLE
Console(config)#interface ethernet 1/1
Console(config-if)#pv6 nd raguard
Console(config-if)#
ipv6 nd
reachable-time
This command configures the amount of time that a remote IPv6 node is
considered reachable after some reachability confirmation event has
occurred.
SYNTAX
ipv6 nd reachable-time milliseconds
no ipv6 nd reachable-time
milliseconds - The time that a node can be considered reachable
after receiving confirmation of reachability.
(Range: 0-3600000)
DEFAULT SETTING
30000 milliseconds is used for neighbor discovery operations
0 milliseconds is advertised in router advertisements
COMMAND MODE
Interface Configuration (VLAN)
COMMAND USAGE
◆ The time limit configured by this parameter allows the router to detect
unavailable neighbors. During the neighbor discover process, an IPv6
node will multicast neighbor solicitation messages to search for
neighbor nodes. For a neighbor node to be considered reachable, it
must respond to the neighbor soliciting node with a neighbor
advertisement message to become a confirmed neighbor, after which
the reachable timer will be considered in effect for subsequent unicast
IPv6 layer communications.