Intermittent problems with LAN transfer speeds

[Adam McLaurin]

Since I first installed FreeBSD 2 years ago, I have intermittent
problems with my LAN transfer speeds. It doesn't happen often, but when
it does, I've not found any solution other than rebooting the server.

My network configuration looks like this:
cable modem --> freebsd 5.1-R --> dlink switch --> win2k workstation

I normally get appx 10MB/s between my two machines. However,
occasionally I'll fire up a transfer and only get 50-200KB/s, which is
really awful.

I've tried rebooting the Win2k machine, disconnecting the ethernet
cables, even power cycling the switch; nothing helps.

The only thing that seems to help is rebooting the server, which I
really hate to do.

I originally had a 3Com card serving the internal network, then I
switched to a Linksys, and now I've got an Intel in there. All 3 have
given me the exact same intermittent problems. 

I've seen this on FreeBSD 4.7, 4.8, 4.9, 5.0, and 5.1.

There is no one else on the LAN but me, so it's not a matter of some
goof misbehaving himself.

I'm really baffled here. 

Here's the output of ifconfig:
-$ ifconfig
fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=3<RXCSUM,TXCSUM>
        inet 192.168.56.2 netmask 0xffffff00 broadcast 192.168.56.255
        ether 00:02:b3:a8:1d:19
        media: Ethernet 100baseTX <full-duplex>
        status: active
dc0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 146.115.***.*** netmask 0xffffff00 broadcast
255.255.255.255        ether 00:04:5a:7b:a7:d0
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active
lp0: flags=8810<POINTOPOINT,SIMPLEX,MULTICAST> mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        inet 127.0.0.1 netmask 0xff000000 


Both the gateway's NIC and the workstations NIC are manually set to
100Mbit full-duplex.

Anyone have any ideas? I'm running ipf+ipnat, if it matters. 

Thanks.

-- 
Adam McLaurin

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