em(4) on FreeBSD is sometimes annoying

Martin nakal at web.de
Sat Aug 2 20:40:50 UTC 2008

On Sat, 02 Aug 2008 12:55:53 +0200
Torfinn Ingolfsen <torfinn.ingolfsen at broadpark.no> wrote:

> Just to be sure: also if the first command you try on the interface is
> 'ifconfig up'?

Hello Torfinn,

good point, no. The problem appears when the first thing called on this
interface is dhclient (caused by ifconfig_em0="DHCP"). I could also
provoke this behavior after the interface was once up had an IP and was
working (ping). All I need to do is to disconnect the NIC from the
switch when I type "/etc/rc.d/netif restart".

I have noticed further strange effects here. The behavior seems to
be even more complex.

After I typed "/etc/rc.d/netif restart", I waited until I get "giving
up" message. Then I plugged the cable in. After about 30 seconds the
link LED was on. I noticed that at this point I couldn't get an address
using DHCP.

So I disconnected physically the NIC (no cable) and link LED was
still on! ifconfig showed me "state: active" with no cable plugged in.
After further 30 seconds the LED went off.

I attached the NIC again to the switch again and after 30 seconds
again I got some other effect. The link LED went on (status: active)
and the data LED was permanently blinking (about 2,5 times a second). I
pulled the cable again and now the link LED is still on and the data
LED still blinking (since about 10 minutes already).

By the way...
Now I'm typing this E-Mail without an ethernet cable plugged in and the
link status LED is still on and the other data LED is blinking.


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