Hi,
I have a pppoe based internet and I have configured everything fine(as I think), but here is what happens:

When I connect I see the IP address, the dns servers and a gateway automatically retrieved from the server, but when I try to ping the servers I get 30% packet loss and on server not in the pppoe ISP network the loss is 70%. http/ftp or any other protocol is not working. The hostname get's resolved, and it starts connecting, and that's it, after a few ftp commands I get time outs.
I have tried different MTU settings/tried setting DNS/gateway manually, but nothing helps.
Do you have any idea what is going on?

P.S The system I am trying it on is not a PC, it's a router, but it's linux based and I can use ssh to login to the router and configure it from the command line.
It uses rp-pppoe for pppoe connections.