[Techtalk] Can I use one gateway/router?

[Chris Wilson]

Hi Rumbi,

On Wed, 25 Jan 2012, Rumbidzayi Gadhula wrote:

> I have setup a shared network with 3 subnets 192.168.0.0, 192.168.2.0, 
> 192.168.3.0, on a linux dhcp server. The server is able to distribute 
> the subnets. My problem is I have one gateway on the network and only 
> one subnet gets access to it. How do I enable the subnets use the same 
> gateway (192.168.0.1) ?

Every subnet needs to have a gateway ON THE SUBNET. In the same way that a 
front door to a house is not very useful unless it's located on the outer 
wall of the house.

Your subnets can use the same physical gateway (router) only if it has 
multiple IP addresses, one in each subnet. They cannot use any address 
which is not in their subnet as their gateway. Some routers support this, 
others do not.

If you have multiple subnets on the same LAN, however, I would strongly 
urge you to combine them into a single larger subnet with a single gateway 
with a single IP address. That way, they can all communicate with each 
other without going through the gateway, which can become a bottleneck.

Hope this helps, Chris.
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