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Here's the situation - I have one cable connection, with router A plugged into, creating network A. I'd like to plug router B into router A (WAN into LAN), creating network B. I'd like to create some separation between these two, so things like shared printers, iPhoto libraries and other network shares don't show up between Networks A and B.

I don't need any high-grade security between the two, it's more for reducing clutter and confusion.

How can I accomplish this scenario?

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Does your router A support VLANs? – MariusMatutiae Nov 16 '13 at 19:25
Differing subnets. – Moses Nov 16 '13 at 19:30
I'm confused by the WAN into LAN can you expand on what you mean by this... – Ben Plont Nov 16 '13 at 20:03
up vote 2 down vote accepted

VLANs are nice, but not needed if you have two routers. Just set up router A normally. For this example i'll assume the network of router A is configured as follow:

Gateway IP:
Subnetmask: (/16 Subnet)
DHCP Range -

You may, of course, vary with your configuration. You can now connect your router B to A. Connect Router B to a normal LAN Port in A. Depending on your vendor, router B will take the incoming connection on the WAN-Port or LAN 1.

If everything is conencted set up Router B with a different Subnet. Example:

Gateway IP:
Subnetmask: (/16 Subnet)
DHCP Range -

Last thing to do is to tell your Router B, that it gets internet using DHCP. Your should find information on that in your manual. Without knowing the router this is - of course - impossible to tell.

If done right all devices connected to router B won't see anything of the Router A network by default. And vice versa. Depending on your router it may be, that a route from network B to A is set up automatically. In that case B devices will be able to connect to A devices, but UDP Multicast etc. won't make it through. If needed it should be possible to delete that route manually.

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Does not work. What will prevent clients of router B from connecting to – MariusMatutiae Nov 16 '13 at 20:21
I thought that was the whole point here: that devices on each network wouldn't see devices on the other network. Or am i reading this wrong in the question. Quote: I'd like to create some separation between these two. BTW I don't even think the second network needs to be on a separate subnet. The router A will keep the traffic apart either way. Devices in B can't reach devices on A (when B is connected through the WAN) because B will block it. – Rik Nov 16 '13 at 20:35
Thanks Chake and Rik - this looks like it will work. Correct I don't need to secure anything beyond normal sharing passwords, just don't need to see those shared libraries anytime someone opens iTunes or iPhoto, etc. – INTJr Nov 16 '13 at 20:43
Glad i could help. @Rik yeah, i thought about that and wasn't entirely shure - so i choose the safe version ;) Sadly i don't have time to dig into that. – Chake Nov 17 '13 at 13:53

VLANs are the way to go if your router supports them.

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