Router Issues & Bugs Blog

There are quite a number of people out there that will share their internet connection with another house. However, most believe that either, both houses must be on the same network/LAN or two networks/LANs and must be isolated (ie, first network cannot access the second).

Lets first layout the the topology so that I can explain the statement above.

1. We have House 1 which has the internet subsciption
2. House 1 and Router 1 setup to access the ISP and it’s IP address will most likely be 192.168.1.1
3. We then have House 2 which is piggy backing off House 1 and sharing the subscription.
4. We have PCs in House 1 using the subscription which we will call PCs 1
5. PCs in House 2 using House 1 subscription which we will call PCs 2

What the majority of people will do when sharing the internet subscription in House 1 with House 2, is that they will setup a wireless connection between Router 1 and PCs 2 directly. The problem with this is that PCs 2 will have varying degrees of performance depending on their location relative to Router 1 and that PCs 2 maybe prone to dropouts. Further, if you sharing files between PCs 2, then performance will be really really bad and should one of the PCs 2 wireless connection dropout, then it will not be accessible for the rest of PCs 2.

The Standard Solution

The standard solution  (that Cisco, DLink, Netgear, etc try to sell you) is the setup a wireless bridge between the two houses. This is basically having 2 wireless access points that can be put into bridged mode, placed in each house. The two access points when placed into bridge mode, will act as if there is a virtual network cable between the two. So what you would do is take Access Point 1, connect it into one of the ports in Router 1 and place in an optimal location relative to House 2. You would then buy a Network Switch plug all PCs 2 into it, position Access Point 2 in an optimal location relative to House 1 and connect it to the Network Switch.

What you have achieved here is the fastest and most stable possible wireless connection between House 1 and House 2 that will not be prone to dropouts. Further more, file transfers between PCs 2 will be at least 10 times faster if not 20 to 30 times.

However, and here it comes, PCs 2 is very heavily dependant on Router 1 and the stability of the bridge between House 1 and House 2. Should Router 1 become offline, it will not only bring down PCs 1 but PCs 2 as well. Better yet, should the bridge become offline, then PCs 1 will still have an active network but  PCs 2 will all be offline.

Basically both houses form 1 network.

The Better Solution

Now that I have aquired my shiney new Cisco e4200 (which leaves my DLink DIR-855 in its dust) I figured l’d move the DLink into the second house and isolate the network (I have 2 houses on my land). So I have the Cisco as Router 1 in House 1 and the DLink as Router 2 on House 2. Basically, I replaced the switch in House 2 with Router 2 and plugged Access Point 2 into the WAN port of Router 2.

A very important note before I go on, you must have a different network address between House 1 and House 2. In my case, Router 1 is on network 192.168.1.0 and Router 2 is set to 192.168.2.0. DLink, by default, use 192.168.0.0 which isn’t good practice, I would avoid using this address, google it if you are interested but I am not going to elaborate on it as I would have to explain subnetting the 192.168 class first.

What you have achieved here is that you have created 2 isolated networks, should anything happen to Router 1 or the bridge, Network 2 and PCs’2 will be unaffected except that they will loose their internet connection.

However, what you will find so far, is that PCs’2 can access PCs 1 but not the other way. This is because the Router 2 is configured as a gateway and is performing NAPT (the manufactures misleading refer to it a NAT). NAPT or network address port translation effectively stops incoming traffic from the WAN port to the LAN if the LAN did not first establish the communication (google it for more details).

DLink routers will not allow you to change the router from Gateway to Router mode, they can be tricked into bridge mode but that will not allow you to create an isolated network. So if you do use a DLink as your Router 2, you will have to contend with double NAPT when access the internet or needless NAPT when accessing Network 1 from Network 2 or vice versa.

You will need to fix the IP address of WAN port on Router 2 for reasons explained later. There are two options here, you can set Router 2 internet connection to DHCP/Automatic IP address, at which case, in Router 1, you will need to set up a DHCP reservation for Router 2. Or you can specify Static IP for your internet connection in Router 2 with the following:

1. IP Address, 192.168.1.2
2. Subnet mask. 255.255.255.0
3. DNS Address. 192.168.1.1

To allow PCs 1 to gain access to PCs 2, you will need to setup static routes in Router 1. Most routers should have this option but will look different in each brand of router. Basically what  you need to enter in is the following:

1. Network Name, in this example, Network 2.
2. Destination Network address, in this example, 192.168.2.0
3. Subnet Mask, 255.255.255.0
4. Gateway, this will be the IP address on the WAN port of Router 2 based on what you chose in the paragraph above.

Where still not quite there.

Even Better solution

If you can, do not use DLink on the second network but perhaps a router that will support DD-WRT/Open-WRT. Then you will be able to add the following in the commands menu:

iptables -I FORWARD -s 192.168.1.0/24 -j ACCEPT
iptables -I FORWARD -s 192.168.0.0/16 -j ACCEPT

This helps with devices trying to discover services on the networks.

Closing Thoughts

If you want to share your Internet Subscription, then you have to learn a little bit about networking. If you want a stable network between the two, then you have to be prepared to spend some money. You don’t need the latest tech, but you will need more network devices and will have to manage them. The good thing about this though, once it is setup, it should not need to be fiddled with. If you can get network devices that use DD-WRT, then the networking world is at your feet but it is a little more effort to become more familiar with it. Finally, based on my experience, DLink products may not be ideal for this.