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icmp redirect question

WorkstationA on LanA sends a packet destined for serverb (on LanB), to it's default Gateway (RouterA). RouterA has a dynamic route in it's routing table to LanB, which it learned via RouterB which also has an interface on LanA.

Q1. Does RouterA send an ICMP redirect to workstationA telling it to go directly through routerB to get to LanB?

Q2.Is the redirect cached in workstationA (windows), so that it uses this redirect throughout the entire TCP connection to workstationB, or does workstation b send every packet to RouterA, which is then ICMP redirected by RouterA?

1 REPLY
Anonymous
N/A

Re: icmp redirect question

1. Yes, it should. "debug ip icmp"

would confirm what is happening.

2. Whether or not the redirect is

cached depends on workstationA; workstationB

does not send any packets to RouterA

(I'm assuming WSB doesn't even know/

care about RouterA), since WSB likely

has a default router (or at least a next

hop address) pointing to RouterB. RouterB

should have a MAC address for WSA, so

the return traffic would go directly

from WSB->RouterB->WSA.

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