Quick Question on source/destination MAC&IP

FloOz

So before I ask my question here is the topology that I am thinking of.

Host1--Switch1--Router1

---

Router2--Switch2--Server2

So lets say Host1 is sending packets with server2. The Source/Destination IP will be Host1IP/Server2IP, and this will not change. The MAC Source/Destination will change as it goes from host1 to router2. So from Router2 to Server2 the Source/Destination MACs will be Router2MAC/Server2MAC.

So here is my issue. When Server2 is responding back to Host1 will the Source/Destination IP still be Host1IP/Server2IP? Or will it change to Server2IP/Host1IP?

Also will source/destination mac be router2MAC/router1MAC when the packet is coming from server2?

Thanks for any help

bwillford

When server 2 replies it will use its IP address as source with host 1 as the destination.

The MAC will leave Server 2 with Server 2's MAC as source and Router 2's as Destination. Then when it gets to Router 1 it will have Router 1 as source and Host 1 as destination.

I think

FloOz

This is what I think too @bwillford. However I was talking to a fellow co-worker and he disagrees

jukem

I also agree with bwillford

networker050184

If the source/destination didn't change how would the packet be routed back?

The source/destination MAC will always be what is need to traverse that L2 segment. So when Server2 sends a packet it will out Router2's MAC as the destination. When Router2 send that packet onto the next segment it will be Router1's MAC. If it tried to put the host's MAC at this point no one would answer as there isn't L2 reachability.