Connecting two LANS to a single cable connection

[Yohhan]

I have 2 BEFSR41 routers. I want to create two seperate home networks (That can NOT talk to one another), that can share my single internet cable connection. I've been told this can be done, but I'm still having problems.

Here's what I've done:
The first router's WAN port is connected to my cable modem. The second router's WAN port is connected to a regular port on the first router.

Linksys tech support told me this should work, but so far, computer connected to the second router cannot access the internet. Both routers are configured to act as DHCP servers. Can anyone give me any points here?

Thanks ahead.

 

[Tallgeese]

What IP settings did you configure on the downstream router (the one NOT directly connected to the modem).

Feel free to use PM, if you don't wanna share such info publicly

 

[Mucman]

I am going to be setting up something similar when I move next week! The new pad will have a shared ADSL connection with th upstairs suite. I am going to setup an
bridging OpenBSD firewall to block all access to my machines except for stuff that I explicitly deny.

The only other way I can see is by using VLANs but I highly doubt you will have the equipment to do that.

 

[FUBAR]

Is it a problem that both of the routers will use the same ip nets and get confused?

I.E. router2 will set the pc's behind it gateway to be 192.168.100.1 which is it's gateway too... is that a problem or does it know how to keep the same ip differentiated between the two interfaces...

Maybe you should set up the ip addresses on the second one to something in the 10.x.x.x network instead.

 

[ButaneBlender]

It would help greatly if you could try pinging each step from the bottom up and telling us the results.

Example:

For this, we'll say the internet router is router A, and the internal router is router B. Can a machine plugged into B ping B's address? (Which I'm assuming is its gateway)
If YES
Can Machine on Router B ping Router A?


Another question that comes up (And I'm sorry if my help is not any help at all) You said you didn't want the two networks to not be able to talk to each other at all? Have you instructed the first router to pass the packets from Router B to it's WAN interface?

And another good point made was that if they are using DHCP, they might be assigning the same address spaces, which will make routing a bit of a problem. You may have to reconfigure one's DHCP scope to a seperate subnet (Example: I use 192.168.0.0/24 and 172.24.0.0/16 in my own internal network)

 

[mboy]

U should assign the WAN port of the 2nd router a static IP based on the subnet of the 1st router (so the WAN side of the 2nd router would be 192.168.100.2, Then change the LAn subnet to say 10.10.xxx.xxx etc.

So in effect, the gateway of the 2nd LAN would be the WAN IP of the 2nd router.

like this: cable modem-----1st router (using DCHP from cable co.)------2nd router(192.168.100.2) and 1st LAN (192.168.2.3-192.168.2.254)---2nd routers LAN IP should be 10.10.xxx.1 and the DHCP sever should dish out the rest. When u check the 2nd routers WAN IP, it should be 192.168.100.2)

Thats should do it.

 

[Fallen Kell]

*nods in agreement with mboy*

The second router can not have the same IP subnet on BOTH sides of the router (i.e. 192.168.1.xxx on WAN, 192.168.1.xxx on LAN). The router routes based off the IP address. If the subnets are the same on both sides of the router, it will never route the packet to the other side, as it will believe that the packet is already on the correct subnet (since the subnet *IS* the same).

 

[Yohhan]

Got it working. I set the WAN IP on the second router to a static address of 192.168.1.2, and then set the internal LAN address to 192.168.2.1. Seems to be working now. Thanks.

 

[mboy]

might want to change the 2nd LAN subnet to 10.10.xxx.xxx so as not to confuse yourself too to much.

 

[DirtylilTechBoy]

192.168.x.x and 10.10.xx.xx are interchangable?

So If I wanted to restructure my IP addressing setup from the 192.168.x.x class to the 10.10.x.x class I could do so as long as they were all changed and anything on the network relating to the 192.168.x.x class was changed over to the 10.10.x.x class?

Thanks

 

[mboy]

yes, both are private. Just make sure 1 router is dishing out the 192.186xxx.xxx and that the second routers WAN Ip isone of those, and make the DCH give out the 10.10.xxx.xxx to the 2nd LAN