Have tried YDL 5 and Fedora Core 6 using PS3 Addon dated 20061208 both with the same issue.
I am unable to run yum update due to "Connection timed out" and unable to browse virtually all web sites except www.google.com and www.youtube.com from what I have tried.
However I am able to ping any\all websites with packet size up to 1472 (so not an mtu issue). It seems that www.google.com and www.youtube.com website truncates all packets down to 64bytes and therefore seem to work with the browsers.
It may seem that the PS3 when sending or receiving large packets, they seem to be corrupted with other traffic on the local network.
Under PS3 XMB, connectivity doesn't seem to be a problem however, its the Internet browsing is slow.
I am unsure if this is a hardware issue specific to my PS3, or there need to be a specific otheros.bld for the PAL PS3 since I haven't found anyone else with downloading issues with PS3 linux.