jinx,
The Marconi probably suffers from the same problem as most of the entry level ADSL routers. The problem is that they don't do real routing on your LAN, just NAT.
What happens is that your Linksys router is assigning an IP address to your client and then routing from that IP to the range which your Marconi is on.
This means, the traffic from 192.168.1.0/24 is passed to the 192.168.10.0/24 range where the Marconi is. The Marconi sees the traffic from 192.168.1.0/24, but, it is only willing to NAT or carry traffic for the 192.168.10.0/24 subnet.
There are three ways to fix this. The first is dikbek's method, setting the subnet mask to 255.255.0.0, thus masking off just 16 bits instead of 24, which will mean that in effect you are using the subnet 192.168.0.0/16, making 192.168.1.0/24 and 192.168.10.0/24 appear to be on the same physical network. In such a case, your Marconi might be willing to route and NAT the traffic from your 192.168.1.0/24 IPs, but I still wouldn't count on it. In fact, I doubt if the Marconi will even let you change its IP address or subnet mask, I've never worked with them, but all I get is bad reviews.
The second method is to set your Linksys router up to perform NAT operations. In this way, traffic from your 192.168.1.0/24 subnet will be masked to appear as if it is coming from the Linksys router's IP on the 192.168.10.0/24 subnet. This will mean the Marconi modem sees only one machine (in this case, your wireless router) on the network. All your wireless machines are hidden from view behind the Linksys. This method is more elegant than the first, and should be possible to set up on the Linksys, but is still not recommended. In effect, you will have a NAT behind a NAT. In such cases, expect problems with some connections, including SSL web traffic, and expect Kazaa/other P2P, IRC DCC and FTP (except for PASV mode) not to work at all.
The third and preferred method to do this would be to set up your Linksys to act only as a wireless bridge. I'm fairly certain it would support such a mode. Check the documentation.
Basically, what you need is to configure the Linksys router, not to route traffic, but only to bridge it from the wireless LAN to your ethernet LAN. Check if the AP has a "client enabled" DHCP mode. I'm sure it should have, possibly by another name, but what you want is a DHCP mode where the AP itself gets its IP via DHCP from the Marconi and also "proxies" DHCP traffic from the wireless LAN to the ethernet LAN. In effect, your Marconi will be handing out IPs to all your machines, and your entire LAN, ethernet and wireless, will appear as if it is inside the same subnet.
Willie Viljoen
Web Developer
Adaptive Web Development
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