Bandwidth Problems with Freebsd 5.x

Danial Thom danial_thom at
Sat Feb 18 10:20:30 PST 2006

--- ptitoliv <ptitoliv at>

> Hello everybody,
> I am writing here because I have a problem with
> network on freebsd 5.3
> and 5.4. The machines are pluged in a 100
> Mbit/s with via rhine network
> cards. On this same LAN  I have a Debian Sarge
> computer. When I try to
> transferts big files beetween the FreeBSD and
> the Debian, I see that I
> have an assymetric bandwith :
> >From Debian to BSD : No problem. The bandwitdh
> is OK : About 8 MBytes/s
> which is normal for a LAN I guess.
> >From BSD to Debian : The bandwidth is quite
> awful => Beetween 300
> KBytes/s to 1Mbyte/s.
> Network have been changed and the problem is
> still the same. So I
> thought it was a network problem. Then I
> installed an other FreeBSD on a
> different computer and plugged it in a
> completely different network and
> the problem is still here. That's why I think
> there is a thing to
> configure on the BSD system but I don't know
> why.
> That's why I am looking here for someone who
> knows this problem and who
> will be able to help me.
> Thank you for your answers
> Best Regards,
> ptitoliv

Are you doing "GET" from each machine, or
comparing GET to PUT? Get has always been a lot
faster then PUT. Put a monitor on the LAN and
look for weird sending patterns. The 4.x FTP
servers will stop altogether if you set the
window under 1500 bytes. I don't know if its the
server app or the stack, but its probably the
specific application, as HTTPD seems not to have
such problems. I think ftp was originally written
by a chimp and no-one has really bothered to ever
fix it (much like nfs). Its quite possible that
socket changes in 5.x made a kludgy
implementation not work as well as it used to.


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