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No1
No1
Posts: 3
Registered: ‎11-18-2010

cascading routers WRT320N - multiple DHCP

Hi all

I´ve 3 pcs of  WRT320N and DSL modem/router (also Linksys, jsut don´t remember whichone). I want to connenct each WRT320N WAN port to LAN ports of modem. These WANs should be something like 192.168.1.10, 192.168.2.10, 192.168.3.10 with mask 255.255.252.0. And I want to run DHCP on each WRT320N to give to computers conected to the WRT320N (cable or wi-fi) the IP from differenta ranges (based on the WRT320N, to which is the computer actually connected).

My point is to make 3 subnets based on 3 WRT320N, that will share one DSL modem/router for connecting to the Internet, but computers from one subnet will not see any machines from other subnets. I also want to allow/disallow services by the source IPs (let say one subnet will not be able to use port TCP 21).

 

Is it clear? And is it possible to do it? 

 

Thanks for help

Zdenek

Expert
Expert
Posts: 12,649
Registered: ‎07-16-2006

Re: cascading routers WRT320N - multiple DHCP

Sure. I don't quite see the purpose of the 255.255.252.0 subnet on the WAN side but if that's what you want...

Are you sure your Linksys DSL modem/router supports 255.255.252.0 on the LAN side? I think by default Linksys devices only support LAN subnets 255.255.255.0 or smaller...

For initial configuration don't connect the WRTs to the main router, yet.

Wire a computer to each WRT open the web interface at http://192.168.1.1/ and configure it on the main setup page, e.g.

Internet connection type: Static IP (unless your DHCP server in the LAN provides the IPs you wanted for the WAN ports of the WRTs.)
IP 192.168.1.10
subnet mask 255.255.252.0
gateway and DNS as required in your main network.

LAN IP 192.168.11.1
Subnet 255.255.255.0

Adjust the DHCP server if you wish.
Save settings.

Now you can connect the WAN port of the WRT to your main router.

The second WRT uses 192.168.2.10 on WAN and 192.168.22.1 on LAN, etc.

Of course you can use different LAN subnets on the WRT if you want as long as it does not overlap with the main subnet, i.e. it's outside 192.168.0-3.

Configure the wireless on each WRT through the web interface.
Configure access restrictions if you need.

Due to NAT on the WRTs the LAN side of each WRT is not accessible from the WAN side.
No1
No1
Posts: 3
Registered: ‎11-18-2010

Re: cascading routers WRT320N - multiple DHCP

Thanks for advices. The mask and IP ranges are not "strict". I can use, whatever is possible by WRTs. The main goal is to create 3 separated subnets connected to one DSL modem, which is GateWay to the internet.

problem:

- I want to have 3 WRTs and on each to run DHCP. But If I assign IPs 192.168.11.1, 192.168.22.1.. to their LANs, I didn´t find a way, how to set DHCP range e.g. to 192.168.xx.100-200. Cause there is fxed "192.168.1" and possible to enter only 1st and last address of the range

 

So, what IP ranges and masks do you prefer to use on subnets? 

 

You wrote "Due to NAT on the WRTs the LAN side of each WRT is not accessible from the WAN side." - I don´t ge it. If I´ll make port forwarding rule (e.g. WANIP:TCP8080 - LANIP:TCP80), it will work, or not? And this can be also done on the DSL modem (e.g. ExternalPublicStaticIP:TCP8080 - WANIPofSpecifiedWRT:TCP8080-LANIP:TCP80). If you ment, that computer from one subnet can´t see computers, printers, NAS... from another subnets, that´s exaclty what I want to do.

 

Thank you very much

Expert
Expert
Posts: 12,649
Registered: ‎07-16-2006

Re: cascading routers WRT320N - multiple DHCP

[ Edited ]

The base address shown for the DHCP server is always derived from the LAN IP address and subnet mask currently in use. After you press save settings the information shown should change. Until then, simply ignore it. Just enter the DHCP server address pool settings as you want and eventually it will all fit. It will work. You don't have to set the first three bytes. They are always determined automatically.

It doesn't matter what IP addresses and masks you use in the LAN. I have suggested some. You can use different ones. It should be private IP addresses.

I still don't see why you wanted a 255.255.252.0 subnet in the main LAN, in particular as that seems to be another Linksys router which most likely won't allow you to set 255.255.252.0 at all. And you do understand that the WAN side and the LAN side of a router must always be exclusive to each, i.e. it must not overlap? You cannot set the WAN side to 192.168.1.10/255.255.252.0 and the LAN side to 192.168.1.1/255.255.255.0.

NAT makes the LAN inaccessible unless you configure port forwarding, port triggering, DMZ host, or enable UPnP on the router.With NAT only packets can enter the LAN which are identified as responses to communication initiated in the LAN before. Your port forwardings you want to do will work.

No1
No1
Posts: 3
Registered: ‎11-18-2010

Re: cascading routers WRT320N - multiple DHCP

Thanks again. I changed IP of router and it changed DHCP range - great.

 

about the 255.255.252.0 - it was just an example which I found somwehere. It´s not necesary for me. As I wrote before - I don´t care about the IP ranges, masks..... I can use whatever public. The main goal is only to have 3 separate networks, which will not have access from one to others and all of them will use one internet conectivity,

 

So, the main LAN is 192.168.10.x/255.255.255.0,  the WAN IPs of routers are from the same segment and LAN of them  192.168.1-3.1/255.255.255.0 and now it works, thanks (inncluding port forwarding)