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What causes a router to send an 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. This informs the host that the best route to reach Host 10.1. 1.1 is by way of router R2. Host H then forwards all the subsequent packets destined for Host 10.1.
What is ICMP redirect support?
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. The ICMP 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.
Do I need ICMP for IPv6?
ICMP is used exclusively with IPv4, and ICMPv6 only exists on IPv6.
How to disable ICMP and ICMPv6 redirects in Linux?
In this tutorial we will learn how to disable ICMP and ICMPv6 redirects on the Linux server. ICMP redirects are used on routers so if your Linux server is not acting as a router then as a general security practice it is recommended to disable the redirects.
Can a ICMP redirect cause a denial of service attack?
While ICMP Redirects are not the very efficient way to update a hosts Routing table of an optimal route to a target destination, it can cause serious security concerns where a hacker or attacker can send malicously crafted ICMP redirect messages and cause a Denial of Service attack on the network.
How to disable routing in Red Hat Linux 6?
Products & Services Product Documentation Red Hat Enterprise Linux 6 Security Guide 2.2.10. Disable Source Routing 1. Security Overview 1.1. Introduction to Security 1.1.1. What is Computer Security? 1.1.2. SELinux
When do you need to use redirects in Linux?
Redirects are only required when a non-default router is preferred for some particular peer addresses, and this knowledge is not hard-configured on the system. The default router will then be initially attempted for sends to those peers and, if it supports redirects, it will respond with one naming the alternate router.