em0 hijacking traffic to port 623

Hi

We've noticed an issue on our firewalls where the first em device
in the system hijacks inbound port 623 tcp and udp.  The OS never
sees this traffic.  Interestingly, em1 and em2 do not appear to be
afflicted by this problem.  Some reading I've done points to a
similar conclusion:

http://blogs.sun.com/shepler/entry/port_623_or_the_mount

I've looked at the bios, but I can't find any settings that remotely
hint IPMI or RMCP+ or serial-over-lan.

Does anyone know how I can stop the card or system from stealing
port 623 in hardware or must I just stop using em0 (and/or Intel NICS)?

Here's the pciconf output:
em0_at_pci3:4:0:   class=0x020000 card=0x10798086 chip=0x10798086 rev=0x03 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = '82546EB Dual Port Gigabit Ethernet Controller'
    class      = network
    subclass   = ethernet
    cap 01[dc] = powerspec 2  supports D0 D3  current D0
    cap 07[e4] = PCI-X 64-bit supports 133MHz, 2048 burst read, 1 split transaction
    cap 05[f0] = MSI supports 1 message, 64 bit enabled with 1 message

Ian

--
Ian Freislich