configuring a wifi router to work with a DSL modem...

[jjoensuu]

Hi all,

I have been trying to get a wifi router (Linksys WRT54GL) configured to
work with a DSL "modem" (Siemens Speedstream 4200) on my Optusnet
account.

PPPoE is used on Optusnet to connect the DSL modem to their server.

The DSL modem has only one ethernet port. This would be used by the
cable coming from Linksys. Linksys on the other hand has 4 ethernet
ports for plugging in devices (and 1 for the cable to the DSL modem).

I have given the DSL modem the following configuration:
-Mode: NAPT (other modes: "Optus Bridge" and "Full bridge")
-IP address: 192.168.1.1
-IP net mask of 255.255.255.0
-default gateway setting of "Use WAN"

Also, the DHCP server functionality is enabled on the DSL modem, with
following settings:
-start IP address: 192.168.1.2
-end IP address: 192.168.1.254
-IP net mask: 255.255.255.0
-default gateway: 192.168.1.1 (itself)
-DNS server: itself
-domain name: Test

Also, the NAT/NAPT settings are "NAPT only enabled", and no static
routes are set.

With these settings, I can access the internet if I plug in my laptop
to the single port on the back.

However, I have not been able to get Linksys to work with it. I have
set Linksys with following settings:
[SETUP > BASIC SETUP]
-Internet connection type: automatic configuration -DHCP
-Host name: blank
-Domain name: Test
-Local IP Address: 192.168.1.2
-Subnet Mask: 255.255.255.0
-DHCP Server: ENABLE
-Starting IP Address: 192.168.1.100

[SETUP > ADVANCED SETUP]
-Operating Mode: Router
-Dynamic Routing: Both (meaning: for LAN & Wireless, and WAN)
Static Routing: none set

I did not think it mattered that both routers are enabled as DHCP
servers, since the Linksys is the only thing that can be connected to
the DSL modem.

However, if connect Linksys to the DSL server and plug in my laptop to
the back of Linksys, I have no access to the internet.

I had this working before but as the lazy bastard I am, I did not
document the configuration.

Does anything look like it is misconfigured, missing, or unnecessary in
these settings?

For example, should the DSL modem be set to work as a bridge of some
sort, rather than in "NAT/NAPT" mode?

thanks,

JJ

 

[Li Wuyi]

Turn off the DHCP funcionality of the DSL and give a static IP to
Linksys(e.g. 192.168.0.100) then let the Linksys allocates the IPs.

 

[Bob Willard]

Turn off the DHCP funcionality of the DSL and give a static IP to
Linksys(e.g. 192.168.0.100) then let the Linksys allocates the IPs.

That will work, but I suggest swapping those IPAs: let the Linksys
use 192.168.1.1, and let the DSL modem use anything other than 192.168.1.*.

That way, when the power fails or the router must be rebooted, it will
use its default IPA of 192.168.1.1 and everything will continue to work.
And, if possible, let the modem use its default IPA (but not 192.168.1.*)
for the same reason.

 

[jjoensuu]

Li Wuyi wrote:
Turn off the DHCP funcionality of the DSL and give a static IP to
Linksys(e.g. 192.168.0.100) then let the Linksys allocates the IPs.

That will work, but I suggest swapping those IPAs: let the Linksys
use 192.168.1.1, and let the DSL modem use anything other than 192.168.1.*.

OK, thanks guys. A couple of follow up questions:

1. About the DNS settings; both the DSL modem and Linksys provides a
way to set the DNS server. Which one should I set these on and what
should it be set to?

2. It seems that Linksys automatically sets itself as the gateway. I
would think that the DSL modem has to be the designated gateway, but
how can this be controlled?

3. Another issue that I do not understand is that I had set the DSL
modem to 192.168.1.1 and Linksys to 192.168.1.2, and both on the same
subnet (255.255.255.0), yet I was not able to ping the DSL modem from
my laptop. The Linksys is the only unit being connected to the DSL
modem (since the modem has only one incoming ethernet port). What can
cause this?

cheers

 

[Bob Willard]

OK, thanks guys. A couple of follow up questions:

1. About the DNS settings; both the DSL modem and Linksys provides a
way to set the DNS server. Which one should I set these on and what
should it be set to?

2. It seems that Linksys automatically sets itself as the gateway. I
would think that the DSL modem has to be the designated gateway, but
how can this be controlled?

3. Another issue that I do not understand is that I had set the DSL
modem to 192.168.1.1 and Linksys to 192.168.1.2, and both on the same
subnet (255.255.255.0), yet I was not able to ping the DSL modem from
my laptop. The Linksys is the only unit being connected to the DSL
modem (since the modem has only one incoming ethernet port). What can
cause this?

cheers

With a standard SOHO setup, in which the PCs connect to the router and
the router connects to the modem, there is no need (other than curiosity)
for the PCs to talk to (via ping or otherwise) the modem; the PCs talk
to the router, and the router talks (through the modem) to the ISP server.
With this setup, I suggest using the router as the DHCP server and setting
each PC to be a DHCP client *and* setting each PC to get its DNS addresses
automatically (which means as part of the DHCP negotiation). With this
setup, the router is the gateway, as can be seen from the PCs using the
IPCONFIG/ALL command (in a command window).

I don't know why you can't successfully ping the modem -- maybe it is set
to not respond to pings. I can ping mine (via the router and with the
standard SOHO setup). Ping failure hardly matters; with this setup, you
might think of the modem as a peripheral device that belongs to the router,
and as otherwise invisible.