[plug] Still not able to route to adsl

[bob]

On Sunday 02 May 2004 14:37, James Devenish wrote:
> Hi,
>
> Are we able to put this thread to bed, soon?

I'm willing to kiss it good night right now (if I can get a working ADSL out 
of it :).

> I'm worried that you might 
> not be getting help because people will be ignoring the rambling nature
> of this situation. I have been hoping that one of the well-known posters
> would step in a set the record straight, but only Matt has stepped
> forward so far. I'm a bit concerned by the thread because, to me, it
> looks like a 'garden-variety' situation that is probably very familiar
> to several of the prominent people on this list, and presumably others
> too.
>
> Now, would I be correct is saying that this summarises your situation:
> >   _________________Host___________________
> >
> >  eth1              eth0                 ppp0
> > 192.168.1.2     192.168.0.1        203.59.131.96
> >
> >   |              ____|____               |
> >   |
> >   |              |   |   |             World
> >
> > 192.168.1.1    Host Host Host
> > ADSL (NB1300+4)
> > a.b.c.d
> >
> > World

Pretty much (although I have been exploring the loping off of the ppp0 
branch as well )

> In this scenario, you know you are fine if you chop off the ADSL branch
> completely, because that's what you previously had. Now, you're telling
> us that it doesn't work if you turn of PPP and try to use ADSL instead,
> is that correct? 

Correct. Also correct is default routing via the ADSL while maintaining the 
ppp0 link.

> Looking at the situation with PPP chopped off, I don't 
> see why you'd be adding lots of manual routes at all. I would think that
> you just need to set a static address for eth0, DHCP your eth1, enable
> forwarding, then enable masquerading. 

Done that (well I think I have...)

> This would amount to four or five 
> lines of ifconfig/route/iptables commands, right (well, on a Debian
> system, you'd set up your loopback and Ethernet interfaces in
> /etc/networking/interfaces so our would only need to enable fowarding
> and masquerading manually)? Hopefully an expert will let us know.
>
> Now, I am not a networking expert, but I can't really see why this
> situation is being problematic. Could one of the experts with PPP
> experience please let us know whether `netstat -r` should show the
> showing something like the following in a functional situation
> (assuming PPP was being used):
>
> Kernel IP routing table
> Destination   Gateway       Genmask         Flags MSS Window irtt Iface
> 192.168.0.0   *             255.255.255.0   U     0      0       0 eth0
> 192.168.1.0   *             255.255.255.0   U     0      0       0 eth1
> 203.69.131.96 *             255.255.255.255 UH    0      0       0 ppp0
> default       203.69.131.96 0.0.0.0         UG    0      0       0 ppp0
>
> Bob: is this what your routing table /used/ to look like? If not, it's
> my fault for guessing wrongly.

Yes, exactly.

route -n
Kernel IP routing table
Destination     Gateway         Genmask        Flags Metric Ref    Use Iface
192.168.1.1     0.0.0.0         255.255.255.255 UH    0      0        0 eth1
203.59.0.x    0.0.0.0         255.255.255.255 UH    0      0        0 ppp0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth1
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
0.0.0.0         203.59.0.x    0.0.0.0         UG    0      0        0 ppp0


> In the above situation, all your Internet traffic is going over PPP
> unless someone happens to know your ADSL router's address, in which case
> they could also interact with your Linux machine in its capacity as
> 192.168.1.2. All your internal hosts would talk amongst themselves
> happily and use 192.168.0.1 as their gateway for Internet access (i.e.
> they would end up masqueraded as 203.69.131.96).
>
> If ADSL were being used instead of PPP:
>
> Kernel IP routing table
> Destination   Gateway       Genmask       Flags MSS Window irtt Iface
> 192.168.0.0   *             255.255.255.0 U     0      0       0 eth0
> 192.168.1.0   *             255.255.255.0 U     0      0       0 eth1
> default       192.168.1.1   0.0.0.0       UG    0      0       0 eth1

Yes, done that.
fluff:~# route del default (gets rid of ppp0 default route)
fluff:~# route add default gw 192.168.1.1

route -n
Kernel IP routing table
Destination     Gateway         Genmask        Flags Metric Ref    Use Iface
192.168.1.1     0.0.0.0         255.255.255.255 UH    0      0        0 eth1
203.59.0.x    0.0.0.0         255.255.255.255 UH    0      0        0 ppp0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth1
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eth1



> And this would just "work" in the same way that PPP worked, except that
> your ADSL router would handle the a.b.c.d<->192.168.1.2 aspect of the
> situation.

That is what I would have thought too.

> Is it possible for you to 'start from scratch' -- even get 
> rid of your firewall perhaps -- and just do 'simple' things (i.e.
> definitely don't go about adding manual routes for all and sundry --
> let your kernel calculate Ethernet routes for the other hosts itself).

Tried that... Nada :(.

I will try that again though as I'm not sure I have covered all the bases in 
this situation.

Thanks for your thoughts :)

-- 
Academic politics is the most vicious and bitter form of politics,
because the stakes are so low.
		-- Wallace Sayre