Concept Guide
Figure 55. ICMP Redirect
Host H is connected to the same Ethernet segment as SW1 and SW2. SW1 and SW2 are multi-layer switches which can route packets. The
default gateway of Host H is congured as SW1. Although the best route to the remote branch oce host may be through SW2, Host H
sends a packet destined for Host R to its default gateway — SW1. After SW1 nds that the route to Host R is through SW2, and that SW1
must forward the packet out the same Ethernet interface on which packet was received, it forwards the packet to SW2 and sends an
ICMP redirect message to Host H. Host H learns of the new route using the ICMP redirect message and sends all future packets to the
remote branch oce host to SW2.
To enable ICMP or ICMP6 redirect messages, use the icmp6-redirect enable command.
NOTE
: The icmp6-redirect enable command is applicable for both ICMP and ICMP6 redirects.
By default, Dell EMC Networking OS supports redirects on VLAN interfaces. For physical ports and port channel interfaces, carve the
fedgovacl CAM region.
UDP Helper
User datagram protocol (UDP) helper allows you to direct the forwarding IP/UDP broadcast trac by creating special broadcast addresses
and rewriting the destination IP address of packets to match those addresses.
Congure UDP Helper
To congure Dell EMC Networking OS to direct UDP broadcast, enable UDP helper and specify the UDP ports for which trac is
forwarded. See Enabling UDP Helper
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IPv4 Routing