I have installed proftpd in my Ubuntu. When I was downloading it was slow enough to make me searching for some answers… Well I found some. Here they are:
#UseReverseDNS — Toggle rDNS lookups UseReverseDNS off #IdentLookups — Toggle ident lookups IdentLookups off
Placing these lines at your /etc/proftpd/proftpd.conf you will get more speed at your file transfers.