By way of clarification, domestic DSL connections are A
DSL, where the "A" stands for asymmetric. The asymmetry is that download is much faster than upload, as the other posters have been pointing out.
Your ADSL connections are a bottleneck - even if 2mbps upload were available to your neighbour (and yours was allowing full 2mbps download) that's still a crawl compared to typical networking speeds, and your ftp server should be able to easily surpass 2mbps. I've just seen over 8 Mbyte / second sending data to proftpd running to a 700Mhz pentium 3 box running Ubuntu 7.10:
From my XP box:
ftp: 50980864 bytes sent in 5.76Seconds 8843.17Kbytes/sec.
On the ubuntu box:
> cat /proc/cpuinfo
model name : Pentium III (Coppermine)
stepping : 6
cpu MHz : 732.344
(they're connected by 100Mbps ethernet via the same switch, and the ubuntu box did have 512M RAM)
If you want to truly measure your ftp *server* performance then do it from the same network. You have ubuntu on your old
PC which implies you have a new
PC also on the network (with windows installed?). Windows (up to XP - don't know about vista) has an ftp client available from the command line (type "ftp"). If you use this to upload a file to your ubuntu box, and they're both plugged into the same router, you'll then get a good idea of the true upload speed.
hope that helps,