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sh ip cache flow


rt01# sh ip cache flow  | i y.y.y.y

Fa0           x.x.x.x  Se0           y.y.y.y  E00 01BB  2893

Fa0          x.x.x.x  Se0           y.y.y.y  06 5FA3 01BB    23

The source interface, the ethernet  address is not x.x.x.x  in this internet facing router.
It is other  public z.z.z..z  ip  .I thought Fa0 source interface output in show ip cache flow should be this public ip z.z.z.z assigned to fa0.But that is not the case.

Please explain how the ip address of FA0 determined

kindly explain.
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3 Solutions
In the above output, Fa0 is the Source Interface on which the packet was received, whereas Source  IP address is the IP address of device that transmitted this packet.

Please type show ip interface brief to see the IP address of Fa 0.


nayan panchal
phoenix26Author Commented:
Hi ,

I believe  the fa0 in the o/p should be the interface ip of the ethernet of the router ;but it is not;
The show ip cache flow fa0 o/p and the ip address configured on ethernet address of router are different

Iam confused with your exp;please help
That's what I am saying.
the packet has been received on Fa0 interface, that's why it is there in the o/p.
the ip address you can see in the o/p is the IP address of the device who transmitted this packet.

You can see the ip address of the interface by typing "show ip int brief" command.

nayan panchal
nrpanchal is correct.

Fa0 is the interface the packet was received on.  The packet had a source IP address of the device that sent the packet (not the router interface).  For example, a PC on the inside connected to y.y.y.y.  In the packet, the PC's IP address is the source IP address.

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