Hey everyone,
After struggling a bit myself with this issue I have found an answer and I thought I would post this up in case any of you are struggling with this also! I've been looking ALL over the internet for help on setting up an ADSL Modem/Router with multiple static IP's and I never found any.
What's even more annoying is, the solution is SO simple.
First of all, you need to make sure you have an ADSL modem that is capable of disabling NAT.
I tried everything and couldn't get anywhere and the nice people at the BT ITSM department (who I called on 0800 500 247) resolved the problem within minutes.
BT gave me the following information:
Gateway IP: 81.xxx.xx.222
Range: 217-221
Netmask: 255.255.255.248
So first of all, I logged into the ADSL Modem, put in my login credentials and disabled NAT.
After that, you need to change the IP Address of the ADSL modem and its internal DHCP range (or disable DHCP) to reflect your details above.
Set the IP Address to 81.xxx.xx.222 and set the subnet mask to 255.255.255.248.
Then, if you have DHCP enabled, set the starting IP as 81.xxx.xx.217 and the end 81.xxx.xx.221.
Now all you need to do is either plug in your devices and let the DHCP assign the addresses, or you can set the IP manually on the device.
When setting it manually, make sure you set the Gateway IP and DNS as 81.xxx.xx.222. For the secondary DNS server, I use OpenDNS's servers.
Then, go to http://www.myipaddress.com to confirm it all...
I hope this is of some help to those of you who were struggling with this the same as I was!!
Cheers
Darren