HP 5500 Ei 5500 Si Switch Series Configuration Guide

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continues to send an NS message. If the interface still does not receive a response after the number of 
sent attempts reaches the threshold (specified with the  ipv6 nd dad attempts command), the acquired 
address is considered usable. 
To configure the attempts to send an NS message for DAD: 
 
Step Command Remarks 
1.   Enter system view. 
system-view N/A 
2.  Enter interface view.  interface 
interface-type 
interface-number  N/A 
3.
  Configure the number of attempts to 
send an NS message for...

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{ The device checks the validity of the existing ND snooping entry. The device sends out a DAD 
NS message including the IPv6 address of the  ND snooping entry. If a corresponding NA 
message (whose source IPv6 address, source MAC address, receiving port, and source VLAN 
are consistent with those of the existing entry)  is received, the device updates the aging time of 
the existing entry. If no corresponding NA message is received within one second after the 
DAD NS message is sent, the device...

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Step Command Remarks 
7.  Configure the maximum 
number of ND snooping 
entries the interface can 
learn.  ipv6 nd snooping max-learning-num
 number
 
Optional. 
By default, the number of 
ND snooping entries an 
interface can learn is 
unlimited. 
8.   Configure the interface as 
an uplink interface and 
disable it from learning 
ND snooping entries.  ipv6 nd snooping uplink  Optional. 
By default, when ND 
snooping is enabled on the 
device, an interface is 
allowed to learn ND 
snooping entries....

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Figure 57 Application environment of local ND proxy 
 
 
Because Host A’s IPv6 address is on the same subn et as Host B’s, Host A directly sends an NS 
message to obtain Host B’s MAC address. However, Host B cannot receive the NS message 
because they are isolated at Layer 2. 
To solve this problem, enable local ND proxy on VLAN-interface 2 of the switch A so that the 
switch A can forward messages  between Host A and Host B. 
Local ND proxy implements Layer 3 communication for two hosts in the...

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Configuring path MTU discovery 
Configuring a static path MTU for a specified IPv6 address 
You can configure a static path MTU for a specified destination IPv6 address. When a source host sends 
a packet through an interface, it compares the interface MTU with the static path MTU of the specified 
destination IPv6 address. If the packet size is larger than the smaller one of the two values, the host 
fragments the packet according to the smaller value. 
To configure a static path MTU for a...

 134 
To configure IPv6 TCP properties:  
Step Command Remarks 
1.  Enter system view. 
system-view  N/A 
2.  Set the synwait timer.  tcp ipv6 timer syn-timeout 
wait-time
  Optional. 
75 seconds by default. 
3.
  Set the finwait timer. 
tcp ipv6 timer fin-timeout wait-time Optional. 
675 seconds by default. 
4.  Set the size of the IPv6 TCP 
sending/receiving buffer.  tcp ipv6 window 
size  Optional. 
8 KB by default. 
 
Configuring ICMPv6 packet sending 
Configuring the maximum ICMPv6
 error packets...

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To enable replying to multicast echo requests:  
Step Command Remarks 
1.  Enter system view. 
system-view  N/A 
2.  Enable replying to multicast 
echo requests.  ipv6 icmpv6 multicast-echo-reply 
enable 
Not enabled by default 
 
Enabling sending of ICMPv6 time exceeded messages 
A device sends out an ICMPv6 Time Exceeded message in the following situations: 
•
  If a received IPv6 packet’s destination IP address  is not a local address and its hop limit is 1, the 
device sends an ICMPv6 Hop Limit...

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If an attacker sends abnormal traffic that causes the device to generate ICMPv6 destination unreachable 
messages, end users may be affected. To prevent such attacks, you can disable the device from sending 
ICMPv6 destination unreachable messages. 
To enable sending of ICMPv6 destination unreachable messages: 
 
Step Command  Remarks 
1.  Enter system view. 
system-view N/A 
2.  Enable sending of ICMPv6 destination 
unreachable messages.  ipv6 unreachables enable 
Disabled by default 
 
Displaying...

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Task Command  Remarks 
Display the IPv6 path MTU 
information. display ipv6 pathmtu
 [ vpn-instance 
vpn-instance-name  ] { ipv6-address | all  | 
dynamic  | static  } [ | { begin  | exclude  | include  } 
regular-expression  ]  Available in any view
 
Only HP 5500 EI 
Switch Series supports 
the 
vpn-instance  
vpn-instance-name  
option. 
Display socket information.  display ipv6 socket
 [ socktype socket-type ] 
[  task-id socket-id  ] [ slot slot-number  ] [ | { begin  | 
exclude  | include  }...

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•  IPv6 is enabled for the host to automatically obtain an IPv6 address through IPv6 ND, and a route 
to Switch B is available. 
Figure 58  Network diagram 
 
The VLAN interfaces have been created on the switch.
 
Configuration procedure 
1.  Configure Switch A: 
# Enable IPv6. 
 system-view 
[SwitchA] ipv6 
# Specify a global unicast addr ess for VLAN-interface 2. 
[SwitchA] interface vlan-interface 2 
[SwitchA-Vlan-interface2] ipv6 address 3001::1/64 
[SwitchA-Vlan-interface2] quit 
# Specify a...