[plug] failing adsl connection

[Craig Ringer]

> This sounds exactly like the problem that I was experiencing. I took 
> responsibility for pppoe away from the modem because I thought I needed 
> the gateway to handle pppoe in order to do IP forwarding.

Port forwarding? I'd assume that most DSL routers would do IP forwarding 
and tunneling as a core function, at least unless you have ATM 
interfaces in your PC. Yes, I'm just being pedantic.

> That's why (I 
> now realise) I started having the error messages and flaky connection. 

Quite possible, assuming that the firewall was still fine but hosts 
behind it had issues. It's easy to set it up so that these issues don't 
ocurr, just make sure rp-pppoe is properly fragmenting packets.

 From /etc/ppp/peers/dsl-provider (debian box, may be elsewhere on other 
distros or with a Roaring Penguin install):

-----
# Use the pppoe program to send the ppp packets over the Ethernet link
# This line should work fine if this computer is the only one accessing
# the Internet through this DSL connection. This is the right line to use
# for most people.
pty "/usr/sbin/pppoe -I eth1 -T 80 -m 1452"

# If the computer connected to the Internet using pppoe is not being used
# by other computers as a gateway to the Internet, you can try the following
# line instead, for a small gain in speed:
#pty "/usr/sbin/pppoe -I eth1 -T 80"

# An even more conservative version of the previous line, if things
# don't work using -m 1452...
#pty "/usr/sbin/pppoe -I eth1 -T 80 -m 1412"
-----

Craig Ringer