ICMP Packet No Response

[williammanurung]

Hi everyone,

I have a problem icmp intermittent between server to server.

this is topology :

I configure monitor span on  Interface Eth1/1, Eth1/2, eth1/40  Switch SF-FARM

And I look something wierd, I got no response packet ICMP on received packet.

The first packet in No 26250 is recieved packet or incoming packet from interface Eth1/1 Switch SF Farm, and the second packet in No. 26251 is transfer packet or outgoing packet via interface Eth1/40.

Why I got no response packet? why received packet need a response?

Best regards,

William

[Seb Rupik]

Hi there,

The wireshark screenshot shows that the reply to the relayed ICMP request is in packet 26252 . Change your wireshark filter to just icmp and you will see the reply.

cheers,

Seb.

[williammanurung]

Hi Seb,

Thanks for join discussion.

Yes, I see reply for packet 26251.

My question is what happen for incoming packet (No 26250)? What's the meaning of no response found message?

[Pawan Raut]

That's might be first packets of ping test usually we see the first packet get drops when initiating the ping due to arp get timeout on switches.

[Seb Rupik]

As your earlier filtering on checksum showed, 26250 and 26251 are the same packet. I suppose what is interesting is that wireshark doesn't flag 26251 as a duplicate. It is probably because wireshark can see that both packets have different Ethernet headers, so it knows it has been switched. So....it knows that 26252 is the reply 26251 as it was received on the same Layer2 segment that it was sent on.