While the best policy for using static IP means we set the DHCP pool to exclude the IP's we want for static assignment this is by no means a requirement.
You can assign any device to any IP you desire. The reason for the exclusion is to prevent other devices from being assigned the IP used by your device.
If we added the pool method information then you would be fine in assigning the IP's without changing the router.
Let me explain.
The NetGear routers pull address from the pool from bottom up. So we know our DHCP IP requests are not going to be assigned higher numbers until we have used up the lower blocks.
Simply knowing the method means we would be safe to assign a static IP above the usable range we expect for our network.
Router|Router IP Address|DHCP Pool Range|Assignment Method|Safe Static Rage
NetGear WNDR3700|192.168.1.1|192.168.1.2 - 192.168.1.254|UP|192.168.1.240 - 192.168.1.253
2-Wire HomePortal 1000SW|172.16.0.1|172.16.1.33 – 172.16.1.250|UP|184.108.40.206-220.127.116.11
2-Wire HomePortal 2700HG-B Gateway|192.168.1.254|192.168.1.64 - 192.168.1.253|UP|192.168.1.240 - 192.168.1.252
Like I said; you should be safe with this method. No need to modify anything on the router at all. We do not expect any DHCP requests to pull IP's from the range selected so using those IP's is as safe as excluding them. It's just not best practice but it will work.
Can't make it any easier for joe installer who does not know networking nor cares to know it.
On your table, how do you conclude that 240 to 253 is 'safe' ?
Other than being on the 'high' range of 1-255 and you assume the DHCP server goes from low to high? Some don't.
Fortunately or unfortunately, joe installer doesn't need to worry about this. . . plus he'd have to know different router brands, user names, passwords . . . ain't gonna happen.
Edited by dennisj00, 23 October 2010 - 06:16 PM.