Hi All,

I'm faced with a networking problem and would appreciate some advice. I am manually capturing and injecting Ethernet traffic (using lib_net/lib_pcap libraries) for an application. At the moment , both capturing and injecting are done on the same physical interface (e.g. eth0). The problem is that all the traffic that I inject, are captured again by my application causing an unwanted feedback of injected traffic. This caused that I had to implement traffic filtering when capturing traffic, which is consuming resources and eventually will become too complicated to support.

I have tried using virtual interfaces to separate the capturing and injecting streams, but that also presented the same problem as all the traffic from eth0 is forwarded to both eth0:1 and eth0:2.

Can someone please give some advice on possible solutions on separating the streams so that no feedback occurs? If possible I would like both streams to go through 1 physical device, using more PDs will be the last resort.

I am also looking at using TUN/TAP devices to try and separate the two streams, maybe writing a user-space program that lies between the physical device and the TUN/TAP devices to do the routing of traffic, but hopefully the Kernel has some way of solving the problem.

Any help appreciated

Arendman
Ubuntu Server 9.04

Can you explain this. If send packets, how can they appear on the receiver?