Static IPs and TP-Link W9970

[jbmangan]

I am tearing my hair out with BT's way of providing static IPs - I have five. With previous suppliers I've signed onto PPPoA and been assigned one of my static IPs and off I go.

I have my own firewall which I usually use with a bridge/modem but, of course, that won't work here so I purchased a TP-Link W9970. I can get connected with that but I still can't work out how to use the static IPs.

I thought I would be able to firewall -> W9970 -> Internet. I was going to set the external IP of the firewall to one static and then turn off NAT on the W9970 but I've tried every configuation I can think of without success (I don't want to write pages about that). Has anyone got this working, please, and f so could you provide some hints? 

[spank]

Hi there,

Think of multiple IP's as NAT Exceptions, or Multi NAT.  Because the setup can be difficult you really need to consider if you need multiple IP's.  Especially if you are not using the BT router.  Some routers handle multi nat better than others.

If you want a static assigned to the router itself then change your BB package to single static, this will assign a static automatically by ISP, the way you expect, and you can use port forwarding.  Call the helpdesk to have this done, it's very quick and easy but they may charge you a £10 fee for the account change.

The only time I would suggest using multiple IP's is if you need to forward the same port to different devices.  For example: if you had three mail servers and had to forward port 25 three different ways.  If you don't, then keep it simple. One static, assigned the the router automatically (it's tied to your user details) is all you need and use port forwarding.

Some users still like the idea of multiple IP's for their devices, for example: IP Cameras, remote desktop, VPN etc.  But....IP cameras can be configured to different ports, remote desktop can have it's ports changed through the registry, and with VPN; you're better buying a VPN router!  If there is an alternative, I would suggest using it.

Multiple IP's will not be assigend automatically, you need to set them up in the router.  How easy that is will depend on the router.

Draytek routers use something called IP aliasing and is very easy to set up.  Other routers don't have this feature and you end up having to configure NAT yourself.  If you cannot create a NAT exception or an additional NAT pool then you will need to turn NAT off completely.

This is not a good situation.

With NAT off you will now need to change the router's LAN address to one of the statics.  This limits the network devices to use the static range only, so if you have 5 IP's you can only have 5 PC's connected.  To get more devices connected you will have to add a new gateway, with NAT enabled, to handle the rest of the network.  This is very messy, I would not reccomend it.

With a firewall you can easily use multiple or single, unless you want to put the router into bridge mode then you're back to all the pitfalls mentioned above.  But with a firewall it doesn't matter if you have to disable NAT on the router, the only device ever connected to the routers LAN will be the firewall.  And although this is possible with multiples, unless you intend to use multiple firewalls it's probably equally as pointless.

So to recap:

• Decide if you really really need multiple IP's:
• If you intend to use port forwarding stick with single.
• If you have a firewall, stick with single unsless you have more than one firewall.
• If you really need multiple IP's  then consider the type of router you have if it's not BT, can it handle multi nat and NAT exceptions?

Thanks