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what is NO IP UNREACHABLES?

what exactly the command "no ip unreachables" or "ip reachables" does?

4 REPLIES

Re: what is NO IP UNREACHABLES?

Re: what is NO IP UNREACHABLES?

Hi,

this command will enable or disable the creation of ICMP unreachable messages. For all details have a look at the command reference:

http://www.cisco.com/en/US/products/ps6350/products_command_reference_chapter09186a0080446279.html#wp1186813

Hope this helps! Please use the rating system.

Regards, Martin

Re: what is NO IP UNREACHABLES?

In addition to the above post i would like to add that a Cisco switch can generate automatically three types of ICMP messages: Host Unreachable, Redirect and Mask Reply. An attacker can use these messages to aid in mapping a network.

Hence these commands are generally disabled on the interface as a security policy.

HTH, rate if it does

Narayan

New Member

Re: what is NO IP UNREACHABLES?

It is worthwhile to understand the fundamentals before seeing how it is implemented:

ftp://ftp.rfc-editor.org/in-notes/rfc792.txt

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