Solved Two Routers on the same Home Network?

November 16, 2010 at 16:41:53
Specs: Windows 7, AMD Phenom II x4/16GB

Hi I hope this request is easy to understand.

I use a cable modem which is a pass-through. It passes the WAN IP to my Router, a D-link DGL-4300, call it DGL-1. My Router is setup to provide DHCP LAN IP Addresses from 192.168.2.100-192.168.2.199. I can use any Static LAN IP from 192.168.2.2-192.168.2.254.

I have a second D-Link DGL-4300, call it DGL-2, that I would like to connect up stairs to provide Wireless as well as direct connection for several other PC's.

I would like to have both routers on the same Sub-Net, say use DGL-1 with LAN IP addresses 192.168.2.2-192.168.2.126, and DGL-2 use LAN IP addresses 192.168.2.127-192.168.2.254.

Can this be done by subnetting?

I already set it up using my second router DGL-2 to get WAN IP from DGL-1, but then I cant use the same subnet for DGL-2, if I use 192.168.1.2-192.168.1.254, the upstairs PC work fine, and get internet. but as far as DNS, I cannot find any of the machines on my first router, DGL-1, unless I map to them by LAN IP.

I hope this makes sense. Just want two routers to split the same subnet and share the Gateway and DNS.

Many Thanks

Kolin


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#1
November 16, 2010 at 21:30:13
✔ Best Answer

Correct setup is as follows;
Logon to router2, assign it an ip in the subnet or router1 lan. if router1 is .1 then assign .2 to router2 for example.
Disable dhcp server
Use a crossover cable to connect router1 lan port to router2 lan port [no crossover required if one of the routers support mdi/mdix]

Everyone is in the same subnet all getting their ip from router1. You have both wired and wireless access

BTW "I can use any Static LAN IP from 192.168.2.2-192.168.2.254" 7
you don't want to use any of the ips in your dhcp scope or you would have an ipconflict.

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#2
November 16, 2010 at 22:32:50

Thank you for the reply.

I went into Router 2 and manually configured the internet (WAN) settings to...

Static
WAN IP 192.168.2.2 (from router 1)
Subnet 255.255.255.0
Default Gateway to 192.168.2.1 (router 1)
Primary DNS Server 192.168.2.1 (router 1)

I had not set or changed the LAN addresses of router 2 yet and I rebooted router 2

Then I went back into router 2 and turned off DHCP Server and set the Router IP address (LAN) to 192.168.2.3 and the subnet mask to 255.255.255.0. When I try to save the settings I get an error message that says "LAN Subnet conflicts with WAN IP".

Did I miss something?

Many Thanks
Kolin


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#3
November 17, 2010 at 06:52:11

Yep, you missed the part lan to lan. Not lan to wan. nothing in the wan interface matters. you assign the ip address to the lan interface.

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Related Solutions

#4
November 20, 2010 at 14:28:55

Hello. I'm in the same situation as Kolin. I haven't configured the network yet but i would have configured the router 2 in the same way Kolin did.
I don't understand Wonderer when you say: "you missed the part lan to lan. Not lan to wan. nothing in the wan interface matters. you assign the ip address to the lan interface."

In my case, in the WAN configuration menu y can choose between static IP or dynamic DHCP. If i choose static IP, then i have to assign a WAN IP (i.e. 192.168.2.2) and a LAN IP (i.e. 192.168.2.3). This scheme has problems as Kolin says. So i would select the DHCP option expecting that router 2 obtains its WAN IP from router 1 and the LAN IP manually from me. My question here is how do i select this LAN IP with the certainty that it won't conflict with any of the IP's assigned by router 1's DHCP ???

Hope to be clear...

Thanks!

Nicolas


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#5
November 20, 2010 at 17:05:39

Good question Nicolas.

In this situation you want to turn the second router into a wireless and wired switch.. If you go thru the wan port you have to route.

After all that's what it was designed to do.

Best for home lan is have everything in the same subnet which means no routing. Bypassing the wan port means no routing. The result you want in the end is just an extension of your original lan.

Part 2:
If you are going lan to wan then you need to route. Assuming a simple setup of one lan and one wan interface to route each needs to be in a unique subnet from the other.

There is a very large scope of what is available.

This can be as simple as;
wan 192.168.0.x
lan 192.168.1.x
x being 0-255 with 1-254 usable

The usual problem is when you add a router its getting/using the same subnet on each side so it doesn't work. It can't route between same and same only between different subnets.

In most cases [first router] you get your wan ip from the modem your ISP provided and you have your lan set to a common class c address range which millions of us use. You are just extending this lan network with the 2nd router.

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#6
November 20, 2010 at 19:00:31

Thanks for the help, worked like a charm.

Incedentially I also asked a tech at D-link and this was his reply.

Hi Kolin,

I’m unsure which feature you are requesting.

The WAN modes for the DGL-4300 are Static IP, DHCP (Dynamic), PPPoE.

If you wish to interconnect the DGL-4300’s, you need to disable DHCP on one of them and change its LAN IP so it does not conflict with the other.

Connect each from LAN to LAN (leaving 3 ports available on each unit).
>>>>>

So it turn out to be soooooo simple, I guess I was complicating things.

Just connect the second router to a LAN port on the first router. You lose one LAN port but you gain the extended network.

Many Thanks

Kolin314


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#7
November 20, 2010 at 19:02:42

Follow-up,

That is connect one LAN port on router 2 to a LAN port on router 1. You dont use the WAN port on router 2.


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#8
November 22, 2010 at 08:30:14

Great! So summarizing...

I see 2 options for expanding the original LAN #1 associated with router 1 (R1), using another router (R2):

1º) Connect both routers between LAN interfaces, this is one LAN port on each router. In this case you miss one LAN port to connect another host on R2.
With this option both routers MUST be on the same subnet but you save the cost of routing. The WAN port on R2 isn't used so there is no need to set a WAN IP on it. Then i supose that there is no need to configure the "Internet conection type" on R2 (it doesn't matter if it is IP Static or DHCP).

Here, which is the default gateway for hosts under R2? Is it R1's LAN IP or R2's? Moreover, how does R2 knows his default gateway is R1?

2º) Connect both routers between LAN interface on R1 and WAN interface on R2. By what i understood, in this way both routers MUSTN'T be on the same subnet, so routing is required. The good side of this option is that you gain one LAN port/interface on R2.

I would like to confirm that with the second option, it is possible to use both routers with DHCP activated. I think it is.

Sorry about my new questions but i want to have the whole idea contemplating all cases.

Thank you very much! Greetings!

Nicolás


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#9
November 22, 2010 at 12:35:03

nicogl

You're overcomplicating a relatively simple situation.

If you're going to keep all clients on one subnet, you DO NOT connect the two routers Lan port to WAN port This method is ONLY used when you want two separate subnets...........period.

Yes, you probably could connect from the LAN port of the upstream router (router 1) to the WAN port of the downstream router (router 2) and keep them in a single subnet. But, this complicates matters a whole lot and in the end, it comes down to one simple question:

"Why would you want to make more work for yourself and overcomplicate something relatively simple by doing it this way?"

We're professionals. We're telling you, in a single subnet scenario you ALWAYS use the aforementioned "LAN port to LAN port" type connection.


Now to address your two (actually 3) questions:

1) In this small an environment there is no "cost" to routing. Routing happens so fast you cannot notice the time taken to open the packet and route it one whole hop by any human sense. As to having one LAN port used up, spend $60.00 USD and buy an 8 port, 1000 Mbps switch and connect it to another LAN port and suddenly, like magic, you now have 10 LAN ports available

If the WAN (internet) port isn't being used then no, you need not configure anything on it with regard to type of internet connection.

NOTE: I've seen some SOHO Routers that have a setting that allows you to use the WAN port as a LAN port. If yours is capable of that, then you could enable that feature, plug router 1 into the WAN port on router 2 (with it acting as a LAN port) and then still have all 4 LAN ports available for clients AND, not have to route

2) Correct, you would only use this method if you're setting up a second, separate subnet.

I would like to confirm that with the second option, it is possible to use both routers with DHCP activated. I think it is.

Since both are on separate subnets, there could be no conflict. Technically speaking you can have two separate DHCP servers running on the same subnet. I've had occasion to do this which I will explain below. The main reason for not doing it though is to avoid problems. With a single DHCP server running in your network it keeps things nice and simple. (If you're not familiar with the KISS principle, google it. We all try our best to live with it in the computing world)

I once setup a training lab using two SOHO Routers in a remote location from our main buildings. Since there were 30 laptops in this training lab, I didn't want to overload a single SOHO router and that's why I had two. I grabbed a block of 30 IP's in the particular subnet we were using for that location and divided it into two. I enabled DHCP on the both routers and assigned half the IP's to one, and half to the other. Something like:

Router 1:
DHCP Scope = 192.168.1.10 to 192.168.1.25

Router 2:
DHCP Scope = 192.168.1.26 to 192.168.1.40

You could do this in any LAN to LAN setup if you really wanted to. But, it adds complexity (again, always apply the KISS principle whenever possible) and makes it possible to screw up your DHCP and have neither one work.

I did what I did above knowing once the 15 IP's for router 1 were used, nobody else could connect to it and would therefore connect to router 2. This kept both from being overloaded.

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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#10
November 22, 2010 at 14:12:32

Curt, thank you very much for your valuable answers.

The only reason in this case why i was complicating things, was to save 1 LAN port on the second router, just that.

I don't know if your post got cut, but i saw you were addressing my questions and i didn't found the answers for this ones:

Here, which is the default gateway for hosts under R2? Is it R1's LAN IP or R2's? Moreover, how does R2 knows his default gateway is R1?

I remember you this questions take place in the first scheme where both routers are connected by their LAN's ports.
I would be very grateful to you if you give me your answers/opinions about this.

Thanks again!

Nicolas


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#11
November 22, 2010 at 14:14:35

I must have missed that question as I was going through them so I'll answer it now

Here, which is the default gateway for hosts under R2? Is it R1's LAN IP or R2's? Moreover, how does R2 knows his default gateway is R1?

The default gateway for R2, connected LAN to LAN, will be the LAN IP of R1

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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#12
November 22, 2010 at 15:11:48

Hi Curt and Nicogl

Just something else to consider...

I originally had my 2 routers setup on 2 subnets. 192.168.2.x and 192.168.0.x.

2.x was the unit with it's WAN to the internet and 0.x was for my upstairs PC's. The thing worked, but what a hassel, when ever you wanted to map a network drive on 2.x you had to go find out what IP the machine that you wanted to map to was on. Even if I set static IP's it was a hassle.

When I set it up where the WAN port from R2 was connected to R1, (Note that router 2 has a Bridge Mode option), It gave me one subnet and the names of all my machings were all listed when searching for a shared device (very slow). But the BIG drawback is that while all the LAN ports on my routers are 1GB, the WAN ports are 100MB, creating a choking hazard...

Clearly the best setup is the simple LAN to LAN (Most greatful to Wanderer), not only do all the shares show up on all machines (very fast), I have a smokin 1GB network, and the Wireless gateway from R2 extends my wireless range.

Many Thanks

Kolin


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#13
March 22, 2011 at 15:50:23

Do you need to reconfigure wireless settings on the second router? Or will this happen automatically?
Thanks!

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#14
March 23, 2011 at 07:33:42

You will need to configure it manually. Use the same SSID and password but put it on a different channel. If router 1 has it's wireless on channel 1, use channel 11 on router 2.

Once configured, wireless clients can connect to the WLAN on router 2 and will get their DHCP settings from the DHCP server on router 1. Which is to say, disable DHCP on router 2. In a single subnet scenario, all wired/wireless connections on router 2 will get their DHCP from router 1

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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#15
July 1, 2011 at 00:57:08

hi Curt, sorry for bringing this topic up again after so long. I am in the same situation.

The thing is if it is the same SSID how do i know which one i am connecting to, R1 or R2? The reason for me to get R2 is to "boost the signal" upstairs.

I have a device that connects to the internet too. Using the lan wire to R2, i it works.
But i have no idea wheather it is working for wirelessly for R2? How to tell?

I am asking this becasue signal strength on my pc can be 4 bars when it is like 2 metres away? pls assist.


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#16
July 1, 2011 at 00:59:00

sorry i missed saying that R1 is also a wireless. Also i noticed that R1 is assigning ips starting from 100 onwards.

Can R2 then be 192.168.1.1? This is the default.


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#17
July 1, 2011 at 06:07:59

The thing is if it is the same SSID how do i know which one i am connecting to, R1 or R2? The reason for me to get R2 is to "boost the signal" upstairs.

Wireless clients will connect to the closest, strongest, signal. This is usually the access point they are physically closest to.

I have a device that connects to the internet too. Using the lan wire to R2, i it works. But i have no idea wheather it is working for wirelessly for R2? How to tell?

If you have it physically plugged into R2 then it should be connecting through it's wired interface. To be sure, disable it's wireless interface.

Can R2 then be 192.168.1.1? This is the default.

What's the LAN IP of R1? Chances are if you're using 192.168.1.0/24 R1 has that IP. You need to use an IP for R2 that's in the same subnet, but outside the DHCP scope so as to avoid duplicate IP's.

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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