1 adsl modem/router + 1 ethernet/wireless router: problem

  • Thread starter Thread starter Bob Bedford
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Bob Bedford

I've 1 ADSL modem (zyxel 650ME) wich is connected to internet.
This ADSL modem is also a DHCP server and may serve up to 4 addresses.
It's default IP configuration is 192.168.1.1
It uses PPOe mode.

I've just bought a LinkSys Wireless router. It has 4 ethernet ports and
wireless access.
It's default IP configuration is also 192.168.1.1
this router has off course DHCP server enabled and may serve many more
connections (up to 50), so I'm not limited to 4 addresses anymore.

What I'm tring to do is configure the linksys as a DHCP server, wich does
serve all my computers's addresses and not to use the modem DHCP feature.
Problem is that I don't know how to set the modem later as it doesn't have
any IP. I don't want 2 subnets, all computers must be visible in the same
192.168.1.X subnet.

How to do so ? I'm quite a newbie in such networking stuffs.
How to set up the modem. Should I disable DHCP, what IP set up to it ?
How to set up the Wireless router ? with DHCP but wich IP ?

Bob
 
You need to replace the DSL Modem with the new Router.

Your DSL Modem isn't really a "modem" if it supplies DHCP,...that would mean
it is also a "router" in spite of what name they call in on the box. In
other words, both Devices are NAT Devices and are in direct competion to
each other. Off the top of my head I see these options.

Option 1
Use the WiFi Router in place of the current DSL Device and replace all the
Nics in your machines with wireless Nics,...unless there is a place on the
WiFi Device to plug in a "wired" hub or switch to tie your existing "wired"
machines into.

Option 2 (in my opinion the best option)
Take the Wifi Router back and exchange it for a Wireless Access Point (WAP).
These devices are simply the equivalent of a wireless hub or switch. They
do not do any "NAT" or "routing" or "DHCP",...they are no different than a
hub or switch other than they are wireless. You simply add them into the
existing LAN just as you would an additional computer. Any machines with
Wireless Nics would connect into the LAN by going through the WAP. The
existing "wired" portion of the LAN remains totally unchanged.

Option 3
I probably should say "non-option 3". You cannot put the two device in a
"series" because you will create a Back-to-Back DMZ between the new WiFi
device and the old wired DSL Device. This will cause your "wired" machines
to be in the DMZ which means they are "untrusted". Any WiFi machines will be
on what would become the new "LAN" on the wireless side. The WiFi machines
could access the wired side (in a limited way) but the wired side would be
"untrusted" and could not access the WiFi side.

The only solution to the above would be if the WiFi "router" can have NAT &
DHCP disabled and have some sort of "bridging" feature. The bridging would
cause both sides of the device to be the same subnet,...in other words it
would act just like the cheaper WAP I mentioned in Option 2. Another
possiblity was if it could act as a true "router" without "NAT",...but I
really doubt that would be the case.

In the end, it is always better to buy the proper hardware for the proper
job in the fisrt place.

--
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
-----------------------------------------------------
Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/ISA2004_AccessRules.html

Microsoft Internet Security & Acceleration Server: Guidance
http://www.microsoft.com/isaserver/techinfo/Guidance/2004.asp
http://www.microsoft.com/isaserver/techinfo/Guidance/2000.asp

Microsoft Internet Security & Acceleration Server: Partners
http://www.microsoft.com/isaserver/partners/default.asp
 
Phillip Windell said:
You need to replace the DSL Modem with the new Router.

Your DSL Modem isn't really a "modem" if it supplies DHCP,...that would
mean
it is also a "router" in spite of what name they call in on the box. In
other words, both Devices are NAT Devices and are in direct competion to
each other. Off the top of my head I see these options.

Option 1
Use the WiFi Router in place of the current DSL Device and replace all the
Nics in your machines with wireless Nics,...unless there is a place on the
WiFi Device to plug in a "wired" hub or switch to tie your existing
"wired"
machines into.

Option 2 (in my opinion the best option)
Take the Wifi Router back and exchange it for a Wireless Access Point
(WAP).
These devices are simply the equivalent of a wireless hub or switch. They
do not do any "NAT" or "routing" or "DHCP",...they are no different than a
hub or switch other than they are wireless. You simply add them into the
existing LAN just as you would an additional computer. Any machines with
Wireless Nics would connect into the LAN by going through the WAP. The
existing "wired" portion of the LAN remains totally unchanged.

Option 3
I probably should say "non-option 3". You cannot put the two device in a
"series" because you will create a Back-to-Back DMZ between the new WiFi
device and the old wired DSL Device. This will cause your "wired" machines
to be in the DMZ which means they are "untrusted". Any WiFi machines will
be
on what would become the new "LAN" on the wireless side. The WiFi
machines
could access the wired side (in a limited way) but the wired side would be
"untrusted" and could not access the WiFi side.

The only solution to the above would be if the WiFi "router" can have NAT
&
DHCP disabled and have some sort of "bridging" feature. The bridging would
cause both sides of the device to be the same subnet,...in other words it
would act just like the cheaper WAP I mentioned in Option 2. Another
possiblity was if it could act as a true "router" without "NAT",...but I
really doubt that would be the case.

In the end, it is always better to buy the proper hardware for the proper
job in the fisrt place.
Click to expand...
Thanks for the answer Phillip.
The purpose of buying the router instead of the WAP is because my modem has
a subnet mask of 255.255.255.248 and I can't change it. So I'm limited to 4
or 6 IP's. Wanting to create a "free spot", this will be limiting. The
router allow 50 connections, and this is the goal of my purchase.

I'd like to disable the modem's DHCP and NAT and allow my new router do the
job, but can't figure out how to do so.
Bob
 
Bob Bedford said:
The purpose of buying the router instead of the WAP is because my modem has
a subnet mask of 255.255.255.248 and I can't change it. So I'm limited to 4
or 6 IP's. Wanting to create a "free spot", this will be limiting. The
router allow 50 connections, and this is the goal of my purchase.

I'd like to disable the modem's DHCP and NAT and allow my new router do the
job, but can't figure out how to do so.
Click to expand...

Then you need to totally replace the DSL "modem" with the WiFi Router. You
"modem" is not really a modem it is a very "low quality" router. Modems do
not have IP#s for themselves nor do they give IP#s to anything else, nor do
they "translate" between the private IP#s they give out and the Public
Internet. If your WiFi Router does not have to built in interface (the
"modem" part) to accept the DSL Phone Line then it will need to have a
"real" DSL modem added to it so it can interface with the Phone Line.

As it stands now you may simply not have the right equipment to do the job.
The ideal situation would be to have a wired NAT Device that has the modem
built in,...then compliment that with a WAP to allow WiFi devices to
function.

For example, with Linksys, you could use one of the BEFSR series of wired
"routers" in combination with a WAP54G or WAP54AG Wireless Access Point.
Just plug the WAP into one of the ports on the BEFSR and you are all set. If
you need more ports just plug a standard hub or switch into one of the ports
on the BEFSR.

--
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
-----------------------------------------------------
Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/ISA2004_AccessRules.html

Microsoft Internet Security & Acceleration Server: Guidance
http://www.microsoft.com/isaserver/techinfo/Guidance/2004.asp
http://www.microsoft.com/isaserver/techinfo/Guidance/2000.asp

Microsoft Internet Security & Acceleration Server: Partners
http://www.microsoft.com/isaserver/partners/default.asp
-----------------------------------------------------
 
Phillip Windell said:
For example, with Linksys, you could use one of the BEFSR series of wired
"routers" in combination with a WAP54G or WAP54AG Wireless Access Point.
Just plug the WAP into one of the ports on the BEFSR and you are all set. If
you need more ports just plug a standard hub or switch into one of the ports
on the BEFSR.
Click to expand...

You have the potential of 254 hosts with this and more if you added a LAN
router to the LAN and created additional subnets. The BEFSR may have a
limit on how many IP#s it will "give out" (not sure if it does or not) but
that is only with respect to DHCP and does not limit you at all since you
can statically assign any address to a machine as long as it is the correct
subnet and the address isn't one that the box gives out with DHCP.

--
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
-----------------------------------------------------
Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/ISA2004_AccessRules.html

Microsoft Internet Security & Acceleration Server: Guidance
http://www.microsoft.com/isaserver/techinfo/Guidance/2004.asp
http://www.microsoft.com/isaserver/techinfo/Guidance/2000.asp

Microsoft Internet Security & Acceleration Server: Partners
http://www.microsoft.com/isaserver/partners/default.asp
-----------------------------------------------------
 
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