packet pass through vs ftp -- performance weirdity

Gary Aitken garya at
Thu Sep 16 07:34:58 PDT 2004

> Happened to me once needed to set the the speed of the nic card in 
> rc.conf can not remember how to do it but it is in the man rc.conf page 
> and solved my similar problem.  Looks something like this if i can recall
> ifconfig_xl0="inet something about manually setting the 
> speed and mode of the card "
> for me it had to do with the card not negotiating it parameters properly 
> and i had to beat it into submission with manual overrides.  glanced 
> through the rc.conf man page but it is to long for me deal with right 
> now the setting are in there somewhere.

This seems highly unlikely, since the same hardware is being used for
the fast case:

Fast   dsl line -- NIC -- FreeBSD -- NIC -- 10MB ethernet -- NIC -- NT

Slow                      FreeBSD -- NIC -- 10MB ethernet -- NIC -- NT

Is this similar to the case you experienced, or was your network
connection to the outside world via a different nic interface?


> Gary Aitken wrote:
>> I'm seeing some weird network performance I don't understand.
>> If I sit at an NT box and using a web browser, go through my fbsd 4.10
>> firewall to someplace out in the world through a slow dsl connection,
>> I get download speeds of 20KB - 45KB/sec, pretty much the max my DSL
>> connection can deliver.
>> The nt box is connected to the fbsd box over a 10Mb/sec full duplex
>> crossover cable for test purposes.
>> If I ftp (shell window) or use a browser to ftp from the fbsd box
>> itself, I see a max speed of something like 8KB/sec.
>> This makes absolutely no sense to me, given the relative speeds of the
>> network connections, which I would have thought was the limiting
>> factor.
>> The fbsd box is a p200, 128M, single 7200rpm 9.4ms seagate ultra scsi
>> drive, 10MB/sec negotiated xfr rate.  Data used for testing was ~8MB
>> file in /var partition, don't know how badly fragmented.
>> Is passing packets through the firewall and ipfw rules that much
>> faster than an ftp access?
>> Ideas for where to look for what's slowing things down?

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