Re: Routing problem...

[Robert Guthrie <rguthrie@pobox.com>]

I'm not going to tell you how to configure the routing of the firewall, as 
I've never done it, but I will give you a very important tip for 
configuring you DSL connection.

First, you'll likely need the pppoe package.  Install it first.  The 
instructions in /usr/share/doc/pppoe will tell you to edit a few files 
related to network connections.  Go ahead and do what they say, but keep 
in mind that you need to migrate those changes into the new way of doing 
things (namely using /etc/network/interfaces for configuring your ethX and 
ppp0 devices).

Note one very important thing with regards to pppoe and masquerading: you 
MUST set all computers on your private network (192.168.1.0) to have their 
network cards' MTU set to 1452.  This is done under linux with the command 
"/sbin/ifconfig eth0 mtu 1452.  I'd recommend putting this in 
/etc/network/interfaces. Here's an example of my entry for one of the 
MASQed computers (address 192.168.2.10):
iface eth0 inet static
    pre-up /sbin/ifconfig eth0 mtu 1452
    address 192.168.2.10
    netmask 255.255.255.0
    broadcast 192.168.2.255
    network 192.168.2.0
    gateway 192.168.2.1

Read up on "man interfaces" and "man ifup" and "man ifdown" to see how 
this works; in the future, all network devices will use these commands and 
configuration files to deal with network devices.

For windows, you have to edit the registry to change this value.  If you 
have Microsoft machines to configure, let me know and I'll send a mail 
from home explaining how to do this (I don't remember the exact entry, so 
I'll have to boot into windows and look at it).

Much of this is mentioned in the DSL HOWTO, but it's not emphasised enough 
for people like me who tend to skim over documents.

Good luck!