[lug] Semi OT: DSL Modem Question

[Lee Woodworth]

Elyse M. Grasso wrote:
> Can someone provide (or point to) an example of how to set up the NAT table in 
> a Zoom X5 (5654) ADSL modem to allow ssh from via the external interface to 
> an internal machine? The manuals don't provide any information 
> about 'advanced' settings and the help files aren't very helpful. 
It may be named something like 'port forwarding'. The concept is to open
the ssh port and instruct the nat/firewall functions to forward packets
between the external (dsl) interface and a specific ip on the lan side.

> 
> I got the Zoom on reccommendations of the gruop here because I wasn't happy 
> with the behavior of the Actiontec that Qwest sold me. I think I had this one 
> behaving properly at one time, but I don't need to set up new computers often 
> enough to remember the settings.
> 
> There is a Linksys router between the PC and the modem.
Is the linksys one of the firewall/nat boxes and are you using
its wan port? If so, you would be doing nat twice. Not usually
necessary.

> 
> Is there any good documentation anywhere about setting up small networks?
Newer editions of:
    Linux Administration Handbook, Nemeth, Snyder & Hein
probably has the information you want, but maybe overkill for you.

A simple case that may apply to you:

phone                      ethernet
~~~~~~~~~~|ADSL  ZOOM  LAN|---------|LAN  LINKSYS  LAN LAN LAN  WAN|-- N/C
                                      |             |   |   |
                                      pc            pc  pc  pc