Splitting Home Network

[theWag]

Setup
Outside world to BT SmartHub WAN
BT SmartHub LAN1 (192.168.2.2) to ASUS RT-N66u(A) WAN (Kid's Network) 192.168.1.###
BT SmartHub LAN2 (192.168.2.3) to ASUS RT-N66(uB) WAN (Parent's Network) 192.168.3.###
BT SmartHub LAN3 to BT TV

Why:
All the kid's stuff goes through Router A so I can monitor usage, add parental controls, schedule WIFI on/off
Want BT TV connected direct to BT SmartHub in case of problems - I have previously configured the ASUS (when it was the only router) for BT TV but when I had signal issues, BT didn't want to entertain troubleshooting until the BT TV box was connected direct to the BT SmartHub

Whats the problem:
Would like to do file sharing, utilise a single printer, single NAS between the A and B network.
Can share the NAS because it has two ethernet port, each is now connected to each network by wire.
When I wirelessly connected the printer to the BT SmartHub, I could ping it from both networks but not print.
Would like to be able to see the PCs on the other network, e.g. have all the laptops / PCs running Windows 7 - 10 in the same homegroup.

As I understand it, the SmartHub is a simple device, not that configurable. In the ideal world, it would be fitting with a routing table I could configure so that if I wanted to ping or fileshare between the networks, it would interpret the IP address correctly and route to the other network rather than out through the gateway to the outside world.
I was thinking about buying another second hand RT-N66u and sitting this between the BT SmartHub and the existing RT-N66 and configuring its routing tables to route traffic between the A and B network or to the outside world. Would that work? Or would a smart switch be capable of this? Given the choice I'd go with RT-N66 probably because the prices are very similar.
Also, with the current setup, why can I ping the printer wirelessly connected to the smarthub (192.168.2.226) but not print to it?

If someone can point me to an idiot's guide for NAT, gateways, WAN, LAN etc.... I'd be grateful

 

[thiggins]

This is an oldie, but may help
http://www.smallnetbuilder.com/lanwan/lanwan-howto/24428-howtotwoprivlan

 

[pege63]

Example 1:

Router 1
Internet IP "address provided by your ISP"
LAN IP address 192.168.1.1
Subnetmsk. 255.255.255.0
DHCP 192.168.1.100-192.168.1.254

Router 2
Internet IP address 192.168.1.2 (connected to router 1)
LAN IP network 192.168.2.1
Subnetmsk. 255.255.255.0
Gateway 192.168.1.1
DHCP 192.168.2.100-192.168.2.254

Router 3
Internet IP address 192.168.1.3 (connected to router 1)
LAN IP network 192.168.3.1
Subnetmsk. 255.255.255.0
Gateway 192.168.1.1
DHCP 192.168.3.100-192.168.3.254

 

[theWag]

Example:

Router 1
Internet IP address provided by your ISP
LAN IP address 192.168.1.1
DHCP 192.168.1.100-192.168.1.254

Router 2
Internet IP address 192.168.1.2 (connected to router 1)
LAN IP network 192.168.2.1
DHCP 192.168.2.100-192.168.2.254

Router 3
Internet IP address 192.168.1.3 (connected to router 1)
LAN IP network 192.168.3.1
DHCP 192.168.3.100-192.168.3.254

 

[theWag]

My setup is basically as you've described but network A cannot see B because, I believe, router 1 is not configurable. Using the addresses in your example, I think router 1 (or its equivalent) needs to be configured so that if it receives a request from router 3 for a destination 192.168.2.101, it should route it to router 2 and not out through the gateway to the internet / drop it. Equally applies for internal traffic from router 2 destined for 192.168.3.101 - router 1 needs to be told what to do with it. The BT Smarthub6 (router 1) isnt that sophisticated hence why I think I need another routing device (1A) sat on LAN side of 1, feeding 2 WAN and 3 WAN from its LAN side?

 

[pege63]

Example 2:

 

[pege63]

Example 3:

 

[pege63]

My setup is basically as you've described but network A cannot see B because, I believe, router 1 is not configurable. Using the addresses in your example, I think router 1 (or its equivalent) needs to be configured so that if it receives a request from router 3 for a destination 192.168.2.101, it should route it to router 2 and not out through the gateway to the internet / drop it. Equally applies for internal traffic from router 2 destined for 192.168.3.101 - router 1 needs to be told what to do with it. The BT Smarthub6 (router 1) isnt that sophisticated hence why I think I need another routing device (1A) sat on LAN side of 1, feeding 2 WAN and 3 WAN from its LAN side?

Do you have the R1 IP in R2 & R3 as Gateway?