H3C Technologies H3C SecPath F1000-E - Manual (Page 119)

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Figure 6 Application environment of ND proxy
Because Host A considers that Host B is on the same network, it directly sends an NS message to obtain
the hardware address of Host B. Host B, however, cannot receive this message because it locates in a
different broadcast domain.
You can solve the problem by enabling ND proxy on GigabitEthernet 0/1 and GigabitEthernet 0/2 of
the device. After that, the device can search the forwarding entries according to the IPv6 address of the
NS message, obtain the outgoing interface and forward the NS message through that interface. In this
case, Host B receives the NS message and responds with an NA message, and the NA message is then
forwarded by the device to Host A. Thus, Router allows communications between Host A and Host B.
Configuration procedure
You can enable ND proxy in VLAN interface view or Layer 3 Ethernet interface view.
Follow these steps to enable ND proxy:
To do… Use the command… Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—
Enable ND proxy ipv6 nd proxy enable
Required
Disabled by default.
Configuring PMTU Discovery
Configuring the Interface MTU
IPv6 routers do not support packet fragmentation. After an IPv6 router receives an IPv6 packet, if the
packet size is greater than the MTU of the forwarding interface, the router will discard the packet.
Meanwhile, the router sends the MTU to the source host through an ICMPv6 packet — Packet Too Big
message. The source host fragments the packet according to the MTU and resends it. To reduce the extra
flow overhead resulting from packets being discarded, a proper interface MTU should be configured
according to the actual networking environment.
Follow these steps to configure the interface MTU:
To do… Use the command… Remarks
Enter system view system-view —
Enter interface view
interface interface-type
interface-number
—