Web Management Guide-R04

Chapter 12 | Security Measures
DHCPv6 Snooping
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If a DHCPv6 Reply packet is received from a server on a trusted port, it
will be processed in the following manner:
A. Check if IPv6 address in IA option is found in binding table:
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If yes, continue to C.
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If not, continue to B.
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Check if IPv6 address in IA option is found in binding cache:
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If yes, continue to C.
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If not, check failed, and forward packet to trusted port.
B. Check status code in IA option:
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If successful, and entry is in binding table, update lease time and
forward to original destination.
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If successful, and entry is in binding cache, move entry from binding
cache to binding table, update lease time and forward to original
destination.
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Otherwise, remove binding entry. and check failed.
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If a DHCPv6 Relay packet is received, check the relay message option in
Relay-Forward or Relay-Reply packet, and process client and server
packets as described above.
◆ If DHCPv6 snooping is globally disabled, all dynamic bindings are removed
from the binding table.
◆ Additional considerations when the switch itself is a DHCPv6 client – The port(s)
through which the switch submits a client request to the DHCPv6 server must
be configured as trusted. Note that the switch will not add a dynamic entry for
itself to the binding table when it receives an ACK message from a DHCPv6
server. Also, when the switch sends out DHCPv6 client packets for itself, no
filtering takes place. However, when the switch receives any messages from a
DHCPv6 server, any packets received from untrusted ports are dropped.
DHCPv6 Snooping
Global Configuration
Use the IP Service > DHCPv6 > Snooping (Configure Global) page to enable
DHCPv6 Snooping globally on the switch, or to configure MAC Address Verification.
Parameters
These parameters are displayed:
◆ DHCPv6 Snooping Status – Enables DHCPv6 snooping globally.
(Default: Disabled)