ICMPv4 Redirect Messages

Every device on an internetwork needs to be able to send to every other device. If hosts were responsible for determining the routes to each possible destination, each host would need to maintain an extensive set of routing information. Since there are so many hosts on an internetwork, this would be a very time-consuming and maintenance-intensive situation.

Instead, IP internetworks are designed around a fundamental design decision: Routers are responsible for determining routes and maintaining routing information. Hosts determine only when they need a datagram routed, and then hand the datagram off to a local router to be sent where it needs to go. I discuss this in more detail in my overview of IP routing concepts (see ...

Get TCP/IP Guide now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.