Intermittent problems with LAN transfer speeds

Q q_dolan at
Wed Jan 7 19:03:28 PST 2004

The first thing you should try is setting the ethernet card to use
autosense. This enables the autosense pulse to be sent to the switch,
without this some passive/unmanaged switches can get very confused and
switch speeds and duplex at seemingly random intervals for a while
before eventually sorting themselves out again. You should only ever set
speed & duplex manually if you can set it at BOTH ends. 

The easiest way to identify this as the problem is to do a 'netstat -i'
and check for collisions. If everything on that LAN segment is full
duplex all the time, there should be none. You will most likely have to
wait for the problem to occur again before the collisions appear.


On Thu, 2004-01-08 at 06:15, Adam McLaurin wrote:
> 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.
> Both the gateway's NIC and the workstations NIC are manually set to
> 100Mbit full-duplex.

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