can MAC addresses be seen between two routers?

[selcuks2001]

Hello everybody,
Can any MAC address information be seen if I sniff the traffic between two routers' serial interfaces?
As far as I know the answer is "NO" but a customer made me feel doubtful about my answer.
The traffic between the routers is Layer3 traffic and there is no information in the IP packet about any MAC addresses of any networks.
Regards...
b^2-4ac

 

[Minue]

Hello
Cool question!Looks like something you would find on a Cisco exam.
In any case I think you are correct because the serial interfaces doesn't use MAC addresses,MAC's are for Ethernet links.
I remember the procces like this:The workstation what's to send a packet to another workstation on another segment.The address is not on the it's local subnet so it arps to find the MAC of it's default gateway and sends the packet.The router will then encapsulate the packet again using the layer 2 protocol on the WAN.Once the packet reach the other router the Ethernet process will start again.I stand to be corrected because I am but Rusty here.I bearly remember this from my CCNA days.
Regards

 

[burtsbees]

Same here---can't remember. The MAC gets stripped and the new one of the next hop gets put on...
Between 2 routers, directly connected, on ethernet you could see the MAC, but not on a serial link.Try that with Wireshark---place a hub between two stations on the same segment, or use SPAN on a switch to capture packets.

"The traffic between the routers is Layer3 traffic and there is no information in the IP packet about any MAC addresses of any networks."

No---the MAC gets stripped at each segment...the info is not sent across networks, but it can be seen if in the same segment.

Burt