Users Guide

In OS10, the MLD snooping and the Unknown Multicast Flood Control feature are enabled by default. Hence, all the unknown
multicast packets are dropped. In this case, the DHCPv6 solicit message is considered an unknown multicast packet and is
dropped.
For the DHCPv6 solicit messages to reach the DHCP server:
1. On the intermediate switch (L2 switch), you must do one of the following:
● Disable multicast snooping flood-restrict globally.
L2switch(config)# no multicast snooping flood-restrict
● Configure the specific VLAN interface as a multicast router interface using the ipv6 mld snooping mrouter
command.
L2switch(config)# interface vlan 10
L2switch(conf-if-vl-10)# ipv6 mld snooping mrouter interface ethernet 1/1/51
L2switch(conf-if-vl-10)# ipv6 mld version 2
L2switch(conf-if-vl-10)# ipv6 mld snooping query-interval 60
L2switch(conf-if-vl-10)# ipv6 mld snooping query-interval 130
L2switch(conf-if-vl-10)# ipv6 mld snooping query-max-resp-time 10
L2switch(conf-if-vl-10)# ipv6 mld snooping last-member-query-interval 1000
L2switch(conf-if-vl-10)# exit
● Disable MLD snooping on the specific VLAN interface.
L2switch(config)# interface vlan 10
L2switch(conf-if-vl-10)# no shutdown
L2switch(conf-if-vl-10)# no ipv6 mld snooping enable
● Disable MLD snooping globally.
L2switch(config)# no ipv6 mld snooping enable
2. On the relay agent, enable MLD querier on the specific VLAN interface.
L2switch(config)# interface vlan 10
L2switch(conf-if-vl-10)# ipv6 mld version 2
L2switch(conf-if-vl-10)# ipv6 mld snooping query-interval 60
L2switch(conf-if-vl-10)# ipv6 mld snooping query-interval 130
L2switch(conf-if-vl-10)# ipv6 mld snooping query-max-resp-time 10
L2switch(conf-if-vl-10)# ipv6 mld snooping last-member-query-interval 1000
L2switch(conf-if-vl-10)# exit
RA(config)# interface vlan 10
RA(conf-if-vl-10)# ipv6 address 3::1/64
RA(conf-if-vl-10)# ipv6 mld snooping querier
RA(conf-if-vl-10)# ipv6 helper-address 3::3
RA(conf-if-vl-10)# ipv6 mld version 2
RA(conf-if-vl-10)# ipv6 mld snooping query-interval 60
RA(conf-if-vl-10)# ipv6 mld snooping query-interval 130
RA(conf-if-vl-10)# ipv6 mld snooping query-max-resp-time 10
RA(conf-if-vl-10)# ipv6 mld snooping last-member-query-interval 1000
Option 82 for security
DHCP, as defined by RFC 2131, provides no authentication or security mechanisms. To ensure security, the DHCP relay agent
supports Option-82 with the Circuit ID sub-option, which is the printable name of the interface where the client request was
received.
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System management