Configuring ICMP Attributes

This section describes how to control the ICMP error packet sending function to prevent ICMP error packet attacks.

Context

Generally, ICMP error packets are used by network-layer or transport-layer protocols to notify the device of anomalies for control and management.

ICMP error packets include ICMP redirect, port unreachable, host unreachable, and timeout packets.

If the function for sending ICMP timeout packets is disabled, the device will not send ICMP timeout packets whose TTL times out, but will send the ICMP timeout packets whose reassembly times out.

Procedure

Access the system view.
```
system-view
```
Enable the fast ICMP reply function.
```
icmp echo-reply fast enable
```
By default, this function is disabled.
Enable the function for sending ICMP redirect packets.
```
icmp redirect send
```
By default, this function is disabled.
Enable the function for sending ICMP host unreachable packets.
```
icmp host-unreachable send
```
By default, this function is disabled.
Enable the function for sending ICMP timeout packets.
```
icmp ttl-exceeded send
```
By default, this function is disabled.
Display the specified interface view.
interface interface-type interface-number
Enable the function for sending ICMP port unreachable packets.
```
icmp port-unreachable send
```
By default, this function is enabled.