For those that want a cheap, easy way to share their SBC DSL with multiple computers, the 5100B CAN be used as a simple router. As the screenshot above shows, the modem is listed as a single device router, meaning that it will only allow one connection. This actually only applies to how many WAN IPs it will pass thru.

To get around this limitation, simply hard code the LAN IPs of the different PCs into the same IP range as the modem. 192.168.0.x, subnet mask 255.255.255.0 and the gateway of 192.168.0.1. Assign the DNS entries appropriate for the area you reside.

Now, just put a switch or hub in and woila!, you now have a very simple NAT router, and can share that DSL. Keep in mind, there are zero advanced features, so if you need those, invest in a dedicated DSL router, however this setup should be sufficient for many who just want to share the DSL and don't want to spend a lot of money to do so.

EDIT--This will also help eliminate the annoying connection drops that happens with WinXP SP2!

Originally contributed by kmac1 at /forum/remark,11542453~mode=flat

Added 12-16-2004: The "visibility" of the LAN-side when using this unit as a simple router was investigated in /forum/remark,12133909~mode=flat :

OK, I tested it and here are my results.

Using the private default IP address of 192.168.1.64 the 5100b doles out via DHCP is totally exposed.Having the 5100b pass the public Internet address results in an identical exposure. Akin to being on a DMZ.

Hardcoding a fixed IP address in the downstream router (or PC) per the "Poor Mans Router 5100b" FAQ (eg. IP=192.168.0.2, Mask=255.255.255.0, DG=192.168.0.1, DNS=192.168.0.1) is NATed and totally Stealth (per Steve Gibson's Shields Up at www.grc.com).

I see no way to (un)stealth it or make it pingable or enable ANY port forwarding when using other than the default private IP address. So it's an ALL or NOTHING scenario. Either totally exposed or totally stealth. Take your pick.

Thanks to JimThePCGuy for raising the question and doing the heavy lifting.

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by RadioDoc edited by lev
last modified: 2005-06-28 13:37:03