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Ace module dropping assymetric layer 2 connections

Hi we had a situation in where the ACE would randomly drop certain tcp connections, and all ICMP packets from a certain windows server.  The server in question was using Transmit Load Balancing with Fault Tolerance.

The server has one Nic connected to Access switch1, and the other nic connected to Access switch2. Each access switch connects up to a pair of 6509's, which is active on Core1 on both switches.

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I am guessing If the server sends on Nic 2, core1 knows it came in on the downstream trunk port to Switch2, it must reply to these packets based on the teamed mac of the layer 3 address(no idea who is arping for the destination - the ace?), and send them back out the downstream trunk port to switch1.  The ace module is in transparent mode.  When contacting a server on the other side of the ace, the ace drop packets that came from the second nic - and I am wondering how it "knows" that the return path is out of different downstream port.  Does it share some kind of layer 2 RPF check with the 6500 ?

Please note there is no routing involved here.  The destination server is just on another vlan on the same subnet, on the other side of the ace.

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