HP 2920 Series User Manual

Disabling ICMP destination unreachable messages
By default, when a HP device receives an IP packet that the device cannot deliver, the device sends
an ICMP unreachable message back to the host that sent the packet. The following types of ICMP
unreachable messages are generated:
The packet was dropped by the HP device due to a filter or ACL configured on the device.Administration
The packet has the "Don't Fragment" bit set in the IP Flag field, but the HP device cannot forward
the packet without fragmenting it.
Fragmentation-needed
The destination network or subnet of the packet is directly connected to the HP device, but the
host specified in the destination IP address of the packet is not on the network.
Host
The HP device cannot reach the network specified in the destination IP address of the packet.Network
The destination host does not have the destination TCP or UDP port specified in the packet. In
this case, the host sends the ICMP Port Unreachable message to the HP device, which in turn
sends the message to the host that sent the packet.
Port
The TCP or UDP protocol on the destination host is not running. This message is different from
the Port Unreachable message, which indicates that the protocol is running on the host but the
requested protocol port is unavailable.
Protocol
The device received a source-routed packet but cannot locate the next-hop IP address indicated
in the packet's Source-Route option.
Source-route-failure
NOTE: Disabling an ICMP Unreachable message type does not change the HP device's ability
to forward packets. Disabling ICMP Unreachable messages prevents the device from generating
or forwarding the Unreachable messages.
Disabling all ICMP unreachable messages
To disable all ICMP Unreachable messages, enter the following command:
HP Switch(config)# no ip icmp unreachable
Syntax:
[no] ip icmp unreachable
For more information, see “Disabling ICMP destination unreachable messages” (page 45).
Disabling ICMP redirects
You can disable ICMP redirects on the HP routing switch only on a global basis, for all the
routing-switch interfaces.
To disable ICMP redirects globally, enter the following command at the global CONFIG level of
the CLI:
HP Switch(config)# no ip icmp redirects
Syntax:
[no] ip icmp redirects
Configuring static IP routes
This feature enables you to create static routes (and null routes) by adding such routes directly to
the route table. This section describes how to add static and null routes to the IP route table.
Configuring static IP routes 45

HP 2920 Series Specifications

General

Brand	HP
Model	2920 Series
Category	Switch
Language	English