MAC Address

[Betsy S. <bst...@us...>]

We have been using iperf to send UDP packets. If we go straight to our
server we get the information about bandwidth, jitter, etc.

We have another server which we access thru a load balancer. This load
balancer changes the MAC header in the incoming packets (changes the src
address only). We do not get the statistics information on this server and
receive the following error at the client:
WARNING: did not receive ack of the last datagram after 10 tries.

I traced the packets in both cases and they look identical except the first
few bytes of data in each packet and in the case that works a return packet
flows from the server to the client after all the data has been
transmitted.

Is there something in the design of iperf that would explain this behavior?