August 2005
Intermediate to advanced
798 pages
31h 12m
English
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Name
ip unreachables — interface
Synopsis
ip unreachables no ip unreachables
Configures
Sending of ICMP unreachable messages for an interface
Default
Enabled
Description
ICMP unreachable messages are generated when something about an incoming packet is unknown to the router. For example, an “ICMP host unreachable” message is generated if the router cannot deliver a package to its final destination. There are many different types of ICMP unreachable messages, and they all mean that the packet can’t be delivered for some reason. Disabling these messages can improve security because the messages can be used to discover information about your network.
Example
The following commands prevent the router from sending IP unreachable messages through the serial0 interface:
interface serial0 no ip unreachables
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.