DELL PE2550 server

eDirectory 8.7.3

NW 6.5 Sp1a: set to 100 / Full duplex

BM 3.8

Cisco switches: set to 100 / Full duplex.
Client 4.83.2

We have problems with an NW 6.5 / BM 3.8 installtion.
This server has 6 NIC's where VLAN's and DMZ's are connected.

The problem is that the users are loosing the return traffic in the
connection through the BM server.

Only 1 or 2 users are connected at the same time.

We have to unload filters - reinitialize system - load filters again
to get it to work again, the problem comes back with intervals
of 2 - 5 days.

This BM server is our inner FireWall, but we have users on the inside
connecting through the BM3.8 srv to another hospital (XY) and

running an Lab application against a MS-Sql database.
The traffic is encrypted using a Cisco PIX connected to a
256 kbps leased line.

_______ ________

-----| BM3.8 |-------| PIX |------- line to

User 1 |_______| 2 |_______ | XY

1 is a mirrored port for BM inside NIC
2 is a mirrored port for BM outside NIC

A nettrace shows that the three way handshake is OK,
The return traffic at 2 is ok, but the return traffic is missing at 1.
At the time we managed to take the trace on the port 1 and had an error
on the connection from our PC, another user connected to hospital
XY from another PC and this return traffic came back OK through the
BM 3.8 and there was no error for this connection.

Anyone seen this kind of problem?

I need advice on how to deal with this.