How to prevent a router from sending out ICMP messages

Answered Question
Dec 22nd, 2012
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Hi guys,


Just wondering if I can somehow to stop my router to send out ICMP "administratively prohibited unreachable" message when icmp packet are being blocked by ACL.

Don't want my router to waste it's CPU resources.



Thanks a lot.


Gleb.

Correct Answer by Pulikkal Sekhar... about 4 years 6 months ago

Hi


It is similar to packets getting process switched.

It can lead to high CPU if you receive lot of such packets which requires to send "icmp unreachables"


Thanks

Raju

Correct Answer by Pulikkal Sekhar... about 4 years 6 months ago

Hi

configure " no ip unreachables" on the interfaces. This will disable sending icmp unreachable messages


Thanks

Raju

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Correct Answer
Pulikkal Sekhar... Sat, 12/22/2012 - 07:21
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  • Cisco Employee,

Hi

configure " no ip unreachables" on the interfaces. This will disable sending icmp unreachable messages


Thanks

Raju

jimmysands73_2 Sat, 12/22/2012 - 09:27
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Just curious....how processor intensive is this to send a simple "administratively prohibited unreachable" message?

Correct Answer
Pulikkal Sekhar... Sat, 12/22/2012 - 18:01
User Badges:
  • Cisco Employee,

Hi


It is similar to packets getting process switched.

It can lead to high CPU if you receive lot of such packets which requires to send "icmp unreachables"


Thanks

Raju

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