icmp limit

From

Maxim Basunov (2:469/142)

To

Eugene Grosbein (2:5054/37.63)

Date

2006-03-04T14:11:54Z

Area

RU.CISCO

Привет Eugene!

 Тут недавно, 04 Мар 06 11:01, пролетала мессага Eugene Grosbein для Maxim
Basunov:
EG>>> Нету rate-limit. По-моему, это общеизвестный факт, что Cisco по
EG>>> дефолту ограничивает свои собственные ответы на ICMP echo request. В
EG>>> частности, этим вызваны "звезды" при трассировке самой Cisco. А вот
EG>>> как это дело отключить, мне неизвестно.
MB>> Стpанно... Уже сколько лет пpовайдеpствую, кошаков с нуля конфигуpю,
MB>> но на этот "общеизвестный" факт не наступал...

EG> Как тут уже подсказали, в глобальном контексте по умолчанию
EG> действует команда ip icmp rate-limit unreachable 500.

Это не имеет никакого отношения к icmp-echo-request/reply.

ip icmp rate-limit unreachable

To have the Cisco IOS software limit the rate at which Internet Control Message
Protocol (ICMP) destination unreachable messages are generated, use the ip icmp
rate-limit unreachable command in global configuration mode. To remove the rate
limit, use the no form of this command.

ip icmp rate-limit unreachable [df] milliseconds

no ip icmp rate-limit unreachable [df]
Syntax Description

df

(Optional) Limits the rate ICMP destination unreachable messages are sent when
code 4, fragmentation is needed and DF set, is specified in the IP header of
the ICMP destination unreachable message.

milliseconds

Time limit (in milliseconds) in which one ICMP destination unreachable message
is sent. The range is 1 millisecond to 4294967295 milliseconds.

Defaults

The default value is one ICMP destination unreachable message per 500
milliseconds.
Command Modes

Global configuration
Command History
Release
Modification

12.0

This command was introduced.

Usage Guidelines

The no ip icmp rate-limit unreachable command turns off the previously
configured rate limit. To re-set the rate limit to its default value, use the
default ip icmp rate-limit unreachable command.

The Cisco IOS software maintains two timers: one for general destination
unreachable messages and one for DF destination unreachable messages. Both
share the same time limits and defaults. If the df option is not configured,
the ip icmp rate-limit unreachable command sets the time values for DF
destination unreachable messages. If the df option is configured, its time
values remain independent from those of general destination unreachable
messages.
Examples

The following example sets the rate of the ICMP destination unreachable message
to one message every 10 milliseconds:

ip icmp rate-limit unreachable 10


The following example turns off the previously configured rate limit:

no ip icmp rate-limit unreachable

The following example sets the rate limit back to the default:

default ip icmp rate-limit unreachable

Dixi.
WBR, Maxim.    [Team - Компьютер должен работать, а человек отдыхать]

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