Strange network behaviour

[Lowell Gilbert]

Vincent Zee <basics at zenzee.cistron.nl> writes:

> On 09 Apr 2003 16:39:03 -0400, Lowell Gilbert wrote:
> > Vincent Zee <basics at zenzee.cistron.nl> writes:
> > 
> >>  I am really at a loss at the moment.
> >>  
> >>  I have a 100baseT network at home and all connected machines have 100Mb 
> >>  network cards.
> >>  When I upload mp3 files from my ibook to the FreeBSD server the speed 
> >>  drops to 100kb/s.
> >>  
> >>  This only happens between these two particular machines. These same 
> >>  machines connected to other machines give the expected transmission 
> >>  speeds. I checked cables, switches and router but found nothing 
> >>  unexpected.
> >>  
> >>  Any hints, ideas or even solutions are most welcome.
> >>  
> >>  The FreeBSD machine is running 4.7 and the ibook 10.2.4
> > 
> > This sounds a lot like a duplex mismatch. 
> > Check the collision count.
> 
> Hi Lowell,
> 
> thank you for your answer(:-))
> 
> Here is the ifconfig output for the nic in the freebsd machine:
> 
> dc0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         inet 192.168.1.10 netmask 0xffffff00 broadcast 192.168.1.255
>         inet6 fe80::248:54ff:fe12:c767%dc0 prefixlen 64 scopeid 0x1 
>         ether 00:48:54:12:c7:67
>         media: Ethernet autoselect (100baseTX <full-duplex>)
>         status: active
> 
> Here is the ifconfig output for the nic in the ibook:
> 
> en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         inet6 fe80::20a:95ff:fe67:2460%en0 prefixlen 64 scopeid 0x4 
>         inet 192.168.1.3 netmask 0xffffff00 broadcast 192.168.1.255
>         ether 00:0a:95:67:24:60 
>         media: autoselect (100baseTX <full-duplex>) status: active
>         supported media: none autoselect 10baseT/UTP <half-duplex> 
> 10baseT/UTP <half-duplex,hw-loopback> 10baseT/UTP <full-duplex> 
> 10baseT/UTP <full-duplex,hw-loopback> 100baseTX <half-duplex> 100baseTX 
> <half-duplex,hw-loopback> 100baseTX <full-duplex> 100baseTX <full-
> duplex,hw-loopback>
> 
> 
> Here is the output of netstat -i during a transmission of a 14 MB file.
> 
> -bash-2.05b$ netstat -i
> Name  Mtu   Network       Address            Ipkts Ierrs    Opkts Oerrs 
>  Coll
> dc0   1500  <Link#1>    00:48:54:12:c7:67  5734078     0  5911495     0 
>     0
> dc0   1500  192.168.1     freeserv         5728716     -  5910566     - 
>     -
> dc0   1500  fe80:1::248 fe80:1::248:54ff:        0     -        0     - 
>     -
> lp0*  1500  <Link#2>                             0     0        0     0 
>     0
> faith 1500  <Link#3>                             0     0        0     0 
>     0
> lo0   16384 <Link#4>                           375     0      375     0 
>     0
> lo0   16384 ::1         ::1                      0     -        0     - 
>     -
> lo0   16384 fe80:4::1   fe80:4::1                0     -        0     - 
>     -
> lo0   16384 your-net      localhost            375     -      375     - 
>     -
> ppp0* 1500  <Link#5>                             0     0        0     0 
>     0
> sl0*  552   <Link#6>                             0     0        0     0 
>     0
> 
> /\
> Vincent

Okay, so there are no collisions on the FreeBSD side.
Check whatever it's plugged into (a switch?).
If *that* thinks the link is half duplex while FreeBSD thinks it's
full duplex, you've found your problem.