[TriLUG] westell usb modem drivers for linux

[Aaron S. Joyner]

Ralph Blach wrote:

> Aaron,
>
> Is there anyway to turn off the Nat translation in the westell modem 
> and simply make it a passthru bridge?
>
> Right now I have two nat translators, my Westell modem and my linksys 
> router.  I would really like my
> my Westell modem to just pass though.
>
> Chip

This depends a lot on which Westel modem you have, and I am not 
intimately familiar with most of them.  In general, something along 
Robert's suggestion is probably correct, there may be a setting, which 
may be obscurely named, which disables NAT in some fashion.  Usually by 
turning the modem from a NAT Router into a DSL bridge.  The tricky part 
about that is that your modem is likely speaking PPPoE or better yet 
PPPoA on the outside interface (over the DSL line).  This means that in 
order to terminate the PPP connection, it has to have the IP address on 
the outside interface.  If you disable the routing functions, and turn 
it into a bridge, you will need to configure your router to do PPPoE 
(less efficient than PPPoA = slightly less bandwidth, due to bigger 
packets).  Making wholesale changes such as this to your internet 
connection is best done with care, as it's hard to google for the answer 
when your DSL modem is borked.  You may also wish to consult with tech 
support for your ISP, who may or may not be willing to walk you through 
the change.

Some newer modems, such as the Zoom that Intrex carried last time I 
looked and others, support something called "half bridging".  This 
essentially terminates the PPP connection on the router, with PPPoA and 
then sets up DHCP to provide only one IP address with a small netmask.  
It then accepts all traffic as if it were your default gateway and 
passes it on unmodified, and accepts all incoming traffic on the 
external IP address and passes it on to your machine (in this case your 
router) unmodified.  It's a neat little networking trick that solves the 
problem very nicely, but unless that's a relatively new Westel, it may 
not support this feature.

All in all, best of luck with your configuration.  If you require more 
assistance with it your ISP is a better source than I am, but if they're 
no help I'll see what I can do.  We should probably take further 
DSL-modem-specific questions off the list.

Aaron S. Joyner