limited transfers

[gbburkhardt at aaahawk.com (Glenn Burkhardt)]

I'd appreciate any ideas you folks have for this problem.

Data transfers to my home machine from our office are limited to small files 
(max file size about 1400 bytes, probably less than one packet).  I'm using 
one of 'ftp', 'ncftp', or 'scp' to do the transfer.  The transfer starts, but 
just hangs.  An empty file is created on the receiving end.

I'm using a dialup line to my private ISP.  Our office firewall/ftp server 
has a T1 link to a different ISP.  It's using current versions of WU-FTPD and 
OpenSSH.  I admit making configuration modifications to increase security, 
since I've noted a number of entry attempts in the logs.  These were limited 
to 'hosts.allow', and the files in /etc/xinetd.d.  But since I can get small 
files but not large ones, it doesn't seem likely to be a access control 
problem.

But here's the funny part.  I have a second computer at home, and am using 
the one with the dialup line as a router.  Everything from the 2nd Linux 
machine works - in fact, it's happily transferring a 16mb file right now.

If I use 'ssh' to log into my office firewall, the same thing happens.  Small 
files can be transferred with 'scp', but transfers of larger ones just hang, 
with an empty (0 byte) file being created on the receiving end.

I've noticed on occasion that when I'm using 'ssh' to log into the office 
machine, if a data transfer is too large, e.g., 'ls' of a large directory, 
the connection hangs.

Other users of our office ftp server report no problems.  If I boot my home 
machine to use Windows, I can ftp to my heart's delight (same machine, same 
modem, same ISP, different OS).

And, if I access a different FTP server, e.g., ftp.gnu.org, I can grab large 
files.

Outgoing/incoming email seems to work for my home machine, regardless of file 
size.

How could I have broken this?  I hate to say it, but I'm about ready to 
through in the towel and re-load Linux on my home machine.  I've spent more 
time trying to figure it out than an installation takes.