Link to home
Start Free TrialLog in
Avatar of lnwright
lnwright

asked on

Get Internet Connection Through Different Subnet

Hi,

I manage a couple of related organisations in the same building.   Both run separte networks and network subnets but there is an Ethernet cable linking the 2.   I want to use the second organisations internet connection as a backup.    Organisation 1 has range of 192.168.0.x   and organisation 2 has a range of 10.0.0.x   Organisation 1 has a gateway router with dual WAN ports.   1 port is connected to it's ADSL modem.  With the other port I want to somehow connect it to Organisation 2's internet connection as a backup.

Appreciate any thoughts.


Avatar of naveedb
naveedb

You may assing the WAN port in the address range of 192.168.0.x and connect it with Organization 2's Network. On the WAN port set the gateway same as Organization 2's Internet Gateway. There with be double NAT but is should work for most application like Web etc.
As a backup of what?? You want to use internet 2 in case internet 1 doesn't works?? What kind of interface is your second WAN interface (serial,ethernet). What kind of routing protocol you are using between the two networks?If there is an ethernet interface connect the ethernet cable and then depending on your routing protocol set the secondary as an alternative link. You should send more details about the devices and the ptotocols you are usimg so that I can send you the exact way you will do that.

Waiting for more details
Avatar of lnwright

ASKER

ykamp,

Yes in case the first connection stops working.

2nd interface is ethernet.

There's an ethernet cable plugged into a switch on each network.

Thanks
If you have connected the router directly to the second network switch it won't work. The packets must be routed!!!. You must connect the second Ethernet interface to the network 2 router. Then you must add two static statements. On router 1 you must add a static route sending all internet packets to the default Adsl (A) interface. This static route must have the best possible metric. Then you must add a second static route with a worse metric sending the internet packets through the second (B) interface. When the router receives the packet , it will check the routing table. If interface A that has the better metric is up all packets will be forwarded through this interface. If it is down packets will be forwarded through the second interface.

Now you must add also two static routes to the router of the second network. When packets have destination IP 0.0.0.0 (internet) it will be forwarded through the wan interface, if there is a destination IP 10.0.0.x it will be forwarded to the internal network. This is easy to set as two static routes are needed.

If you have connect the Ethernet cable that connects the two networks from router 1 directly to switch 2 sorry but there is  now way to forward packets as the switch is not capable to do so sending packets to the default gateway of the second network.  


ykamp:

It will work, he is doing NAT on both routers.

[LAN-1]---[ROUTER-1]--NAT--[WAN-1]--[INTERNET]
                            \----NAT--[WAN-2]--[LAN-2]--[ROUTER-2]--NAT--[INTERNET]
Are there two routers???? I've told him that he needs two routers but he doesn't say anything about having two routers, does he????? If he has two routers I two router I think my way also works.
Thanks guys,

Yes there is a router on each network.

>If you have connect the Ethernet cable that connects the two networks from router 1 directly to switch 2 sorry but there is  >now way to forward packets as the switch is not capable to do so sending packets to the default gateway of the second >network.  

Yes I assumed I'd have to tell Router 1 the address of the 2nd router.    I like what naveedb has said:

>[LAN-1]---[ROUTER-1]--NAT--[WAN-1]--[INTERNET]
>                           \----NAT--[WAN-2]--[LAN-2]--[ROUTER-2]--NAT--[INTERNET]


The only thing is, I'm not sure that router 2 will talk to a router from a different subnet.













ASKER CERTIFIED SOLUTION
Avatar of naveedb
naveedb

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Thanks naveedb,  that makes sense.
It will work, this is router's job. Static route job is to help networks that are in different subnet to communicate. In case static routes don't work use RIP. RIP really easy to setup and administrate.

If naveedb way doesn't work, try mine..you will love it