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HAPTER
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| IP Configuration
Setting the Switch’s IP Address (IP Version 6)
– 574 –
◆ ND Reachable-Time – The amount of time that a remote IPv6 node is
considered reachable after some reachability confirmation event has
occurred. (Range: 0-3600000 milliseconds; Default: 30000
milliseconds)
◆ Restart DHCPv6 – When DHCPv6 is restarted, the switch may attempt
to acquire an IP address prefix through stateful address
autoconfiguration. If the router advertisements have the “other stateful
configuration” flag set, the switch may also attempt to acquire other
non-address configuration information (such as a default gateway)
when DHCPv6 is restarted.
Prior to submitting a client request to a DHCPv6 server, the switch
should be configured with a link-local address using the Address
Autoconfig option. The state of the Managed Address Configuration flag
(M flag) and Other Stateful Configuration flag (O flag) received in
Router Advertisement messages will determine the information this
switch should attempt to acquire from the DHCPv6 server as described
below.
■
Both M and O flags are set to 1:
DHCPv6 is used for both address and other configuration settings.
This combination is known as DHCPv6 stateful autoconfiguration, in
which a DHCPv6 server assigns stateful addresses to IPv6 hosts.
■
The M flag is set to 0, and the O flag is set to 1:
DHCPv6 is used only for other configuration settings.
Neighboring routers are configured to advertise non-link-local
address prefixes from which IPv6 hosts derive stateless addresses.
This combination is known as DHCPv6 stateless autoconfiguration,
in which a DHCPv6 server does not assign stateful addresses to
IPv6 hosts, but does assign stateless configuration settings.
RA Guard
◆ Interface – Shows port or trunk configuration page.
◆ RA Guard – Blocks incoming Router Advertisement and Router
Redirect packets. (Default: Disabled)
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, note
that 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.
RA Guard 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.
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