Question on bandwidth limiting

Hi.

We have a Fedora Core 2 box that exhibits some kind of download
throttling behaviour. If I enter

wget --proxy=off http://<url of a 9Mb download>

then the downloads begins well enough, reaching a rate of around 190Kb/s
by which time it has abour 450K of the target file. (The amount of file
downloaded varies for each attempt, but it's usually between 300K and
600K.) After this point (about 4 - 6 seconds) the download slows to a
trickle, < 1K/s ultimately.

Other machines on the network work fine, so it's not the router,
firewall, or web server. It may not be a bandwidth limiting thing (any
suggestions welcome) but that's what it looks like.

My question is: Where do I start looking to find out what the problem
might be?

I don't know anything about bandwidth limiting on Linux, apart from the
various HowTos that I've skimmed. All of them assume that you want to
_add_ some form of limiting, not _remove_ it, so I don't know how best
to find out what might be causing the problem.

Any ideas?

Thanks,
Colin MacDonald