half-duplex

[Sam Wun]

Hi,

I am running a FreeBSD 5.4 stable as a network router.
I don't know any reason why one of the ethernet ports becomes half-duplex.
Here is its detail:

em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=b<RXCSUM,TXCSUM,VLAN_MTU>
        inet 60.1.2.3 netmask 0xfffffffc broadcast 220.233.99.39
        ether 00:04:23:bc:3a:d1
        media: Ethernet autoselect (10baseT/UTP <half-duplex>)
        status: active
em2: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=b<RXCSUM,TXCSUM,VLAN_MTU>
        inet 10.1.10.1 netmask 0xffffff00 broadcast 10.1.10.255
        ether 00:04:23:bc:3a:d2
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active

This network card is a Quat Port Intel card.
Is there any way I can "reset" it to full-duplex and 1000baseT without close
down the network connection on em1?
I know I can use following command to change it:
ifconfig em1 media 100baseTX mediaopt full-duplex

but if this not work, it will close down the entire internet connection,
which I try to avoid.

Thanks
S