In routers, 'no ip redirects' keeps the router from sending ICMP redirect messages to clients.
Redirects are used by a router when it knows that a better path exists for a client other than itself. A router will send a ICMP Redirect to the client pointing it to a different next-hop for a given destination in hopes the client will take this new path to this destination.
Redirects can be disabled for security reasons. It's possible a rogue router could enter the network with "better" paths but malicious intent. Therefore, we would want to avoid giving hosts a reason to change their path to the new, malicious router.
Here's a Cisco doc on when / why redirects are used:
Just to expand a little futher on this. Many time end device won't change their behavior when recieving an ICMP redirect, in this case the router just keeps sending redirects over and over. Doing this causes more work for the CPU as we have to craft the ICMP redirect packet. Due to this, many times its just easier to allow the host to continue sending the packets to the current router.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
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