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What is a ICMP redirect?
ICMP redirect messages are used by routers to notify the hosts on the data link that a better route is available for a particular destination. Router R1 forwards the packet to router R2 and also sends an ICMP redirect message to Host H. This informs the host that the best route to reach Host 10.1.
Is TCP A ICMP?
ICMP gives TCP/IP a way to handle errors. Any network device that is using TCP/IP has the capability to send, receive, or process ICMP messages. ICMP also has a method in place to prevent multiple messages for the same error in the way that error messages are sent in response to fragmented traffic.
Where does the ICMP redirect message go to?
The gateway, L3 Switch, checks its routing table and obtains the address 10.0.0.2 of the next gateway, G2, on the route to data packet’s destination network, X. 3. If G2 and the host identified by the source address of IP packet are on the same network, ICMP Redirect message is sent to the host.
Is the ICMP redirect cache empty on 4510?
ICMP redirect cache is empty And when excecuting it on other switches like 3850 and 4510, they actually show a routing tables with a couple entries like the connected, local and static route out of the switch.
How to disable ICMP redirects on Layer 3 interfaces?
In fact, for most networks it is a good practice to proactively disable ICMP Redirects on all Layer 3 interfaces, both physical, like Ethernet interface, and virtual, like Port-Channel and SVI interfaces. Use no ip redirects NX-OS interface-level command to disable ICMP Redirects on a Layer 3 interface.
When to send a redirect message to a host?
If G2 and the host identified by the internet source address of the datagram are on the same network, a redirect message is sent to the host. The redirect message advises the host to send its traffic for network X directly to gateway G2 as this is a shorter path to the destination.