2 wire DSL

[Luke Militello]

Leonard Chatagnier wrote:
> --- On Sat, 12/6/08, Luke Militello <luke at digitalenigma.net> wrote:
> BIG SNIP
>> Sounds to me the problem is a double NAT.  From what I am
>> reading... is 
>> this how your network is setup?
>>
>> INET <----> 2WIRE-DSL <----> WIFI-RTR
>> <----> END-USERS
>>
>> Most DSL routers do NAT by default, however lack the option
>> of WiFi 
>> capabilities so most users opt for a secondary router.  If
>> your network 
>> is like the one above, then your WiFi router is
>> "NAT'ing" down to one IP 
>> address on the "DSL network".  Although double
>> NAT is bad for port 
>> forwarding and I wouldn't recommend it, it can be done,
>> however you must 
>> be sure the two private ranges are not conflicting.  In
>> other words, if 
>> the device doing NAT sees the same network on each side, it
>> will get 
>> confused.  If this is the case, do something like this.
>>
>> INET <----> 2WIRE-DSL <--(192.168.1.0/24)-->
>> WIFI-RTR 
>> <--(192.168.2.0/24)--> END-USERS
>>
>> You will still have double NAT in place, but this should
>> allow 
>> connectivity to 192.168.1.254 (your DSL box).  Because this
>> IP address 
>> only exists on one side, your WiFi router would treat it
>> like a "public" 
>> IP and translate it just fine.  Feel free to use any of
>> these networks 
>> as they are all reserved for private use.
>>
>> 10.0.0.0/8 (10.0.0.0-10.255.255.255)
>> 172.16.0.0/12 (172.16.0.0-172.31.255.255)
>> 192.168.0.0/16 (192.168.0.0-192.168.255.255)
>>
>> However, the best approach would be to directly connect one
>> PC to your 
>> DSL box (via DHCP), login and disable NAT, connect your
>> WiFi router back 
>> up, reboot both DSL and WiFi router (in that order), then
>> login to your 
>> WiFi router and verify for its public address that it does
>> NOT have an 
>> IP address which falls in the ranges given above.
>>
>> One more thing to mention, most DSL routers will
>> automagically disable 
>> NAT once they see a connection to the WAN/DSL/Internet
>> side.  In this 
>> case, your network should be fine.  Simply disconnect the
>> DSL box from 
>> the phone line, reboot it and you should get connectivity
>> to 
>> 192.168.1.254 for management purposes.  Once plugged back
>> in to the 
>> phone line, connectivity to 192.168.1.254 will go away. 
>> However, to do 
>> this, I would plug a PC directly into the DSL box to avoid
>> network 
>> confusion if you WiFi router uses the same network as your
>> DSL box (as 
>> stated above).
>>
>> Hope this helps, if not, please enlighten me on your
>> network setup as 
>> there are too many posts for me to trace back on ;)
>>
>>
>>
> Honestly, Luke, I have no idea what you mean at the beginning
> of your reply so let me try to explain.  Two machine LAN.  Outside
> world connected to 2wire DSL router/ modem combo.  Router wired
> to new Gateway Intrepid machine which is now in shop so I have no
> hard wired maching in place currently.  The other machine in anther
> room has a syslink wmp54g wifi card installed and a NIC also but
> not connected to anything.  The eth0 interface is setup with same
> IP as the wifi.
> I don't know about NAt either and If I understand what you said
> I don't have a separate router and modem.  They are all in one box,
> a 2wire 1701hg router/modem combo.  I've only had experience 
> with this one router.modem combo.  it seem that you refer to
> each separately above, but I'm not sure.  In any case, I'm about
> to move the wireless machine and hook it up directly to the
> router/modem(after unplugging it to reset) and start the machine
>  back up under DHCP to see if I can connect to 192.168.1.254 and
> access the 2wire setup page again.  Hope this explains a liitle.  I
> know what you mean, I've been answering replyies on this issue all
> day and haven't had time to move the machine or switch back to DHCP
> yet but will do so now.   Thanks for you input.  Sorry I didn't uderstand
> most of it but I did say I was a network idiot in an earlier post.
> Leonard Chatagnier
> lenc5570 at sbcglobal.net
> 
> 
> 

No, problem, that does clear some stuff up so ignore the bulk of my last 
reply.  So to clarify, you have (right now) one PC connected via 
wireless to your 2Wire DSL.  You can connect to the Internet just fine, 
but cannot connect to the 2Wire?  Try this command...

[luke at Ignignokt ~]$ netstat -nr
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt 
Iface
10.188.39.192   0.0.0.0         255.255.255.192 U         0 0 
  0 eth0	<-- My local network.
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0 
  0 eth0	<-- If you have this as well, ignore it.
0.0.0.0         10.188.39.193   0.0.0.0         UG        0 0 
  0 eth0	<-- My default gateway.


See where I have "10.188.39.193"?  That is my default gateway hence the 
"G" flag.  In your case, is yours 192.168.1.254?  If it is something 
different, that is most likely the IP address of your 2Wire.  Try 
connecting to whatever IP address is listed there in Firefox.

-- 

Luke J Militello, CCNA
Network Engineer
Technical Operations
Charter Communications
Cisco Certified Network Associate
Michigan Technological University, BS
Computer Network & System Administration