How to use Public Static IPs with BT Hub 3/BT Infinity

[DAFlippers]

I ordered a Static IP range and thought it would be simple to set up port forwarding to Cameras etc. but it wasn't.

BT can give you a single static IP where this would be possible but this isn't what I wanted.  I wanted the flexibility of multiple public IPs.

If you have a range of IPs either 8 (5 usable) or 16 (13 usable) BT actually assign your router with a Dynamic IP outside your range of static IPs - thus using up an extra IP.  This is done to 'add a further level of security' and the user does not have the option to forgo this by assigning a usable Public IP to the BT router.  This means if you want to have devices assigned public IPs you need to set them up in the BT Hub as individual devices. 

Now rather than assigning each device a Public IP address I wanted to place a Firewall/Router to cushion the devices.  To do this I did the following:

• Set Static IP on BT Hub - set router (BT Hub) address to the Public address in your email welcome letter - it will be one above your highest usable IP.

• Get a Firewall/Router -I chose a cheap and cheerful TP-Link TL-WR743ND set up a subnet (make sure it is a different number from your main network) and set the WAN port to Dynamic IP.

• Assign Static IP to Firewall/Router - via configure button on Static IP page of BT Hub set up.

• Set up Port Forwarding on Firewall/Router - you can check these work by using browser/application from computer on main (BT Hub) network and use the Public IP address/ports.  This checks the port forwarding is set up *but* the Public IP addresses are not really public yet as you are looping back through the BT Hub.

• Set up Port Forwarding on BT Hub - the BT Hub Firewall for whatever reason is still protecting users from the outside world by blocking all incoming traffic to the Public IP address assigned to the Firewall/Router so you need to repeat all the Port Forwarding you set up on the Firewall/Router on the BT Hub except all forwarding is to the Firewall/Router and not the devices.

All this may sound complicated but it is fairly straightforward but not documented so hopefully this will help others.

Preventing IP range users assigning the BT Hub a usable Public IP address in the same way single static IP users are set up *may* be permitted with IPv6 but I had to work the above out for myself with a little help on the very last step from BT - I knew it was a Firewall issue because disabling the BT Hub Firewall made it all work. 

LMK if you need further clarification,

David

[DAFlippers]

I have found that only the last rule applied works so wrap all your port forwarding to the Firewall/Router into a single rule and only apply that single rule.

David

[jaketehcatuk]

If you are on Infinity, you can bin the hub completely and plug your firewall directly into the VSDL modem.

Provided you firewall can establish a PPPOE connection and recive a DHCP address, it will work.

You then get to use six of your eight allocated addresses and you get rid of the pile of rubbish BT hub.

[DAFlippers]

Understood and I'm sure that is a cleaner solution but I wanted to see what was possible with minimum change to installed solution.  I'm sure any support from BT would require BT Hub to be in place otherwise you are on your own - I appreciate the irony in that statement.

Also the TP-Link wireless Firewall Router was under GBP28 delivered and not a bad device.  It also gives me a separate subnet with WiFi so I'd need an additional wireless router anyway. 

David

[adrianc]

"You then get to use six of your eight allocated addresses..."

You mean 6 of your 5 allocated addresses - BT doesn't sell an 8 IP product.

[DAFlippers]

Depends on how you look at it.  BT sells 8 or 16 Static IP range of which 5 or 13 are usable.  I presume if you use your own hub then the one assigned to the BT hub becomes available to the outside world.  that would mean 6 of the 8 (or 14 of the 16) would then be available.

Of course if you have a Static IP range and you use a BT hub you have 5 (or 13) usable static Public IPs and 1 dynamic Public IP.

David

[adrianc]

Yeah, I was being pedantic - the point is that BT only 'rent' you 5 IP's so YMMV as far as using the 6th IP in the range is concerned.

Adrian

[DAFlippers]

Hi Adrian,

I agree.  The BT Static IP offering is not quite what I expected but with a little work I was able to do what I wanted to do. 

Why they insist on assigning a dynamic IP for the BT Router if you have a Static IP Range is beyond me.

David

[mikej101]

I completely agree with you on the dynamic IP thing ! I had no problems with using 3 of the 5 static IP's when I was using the old 2700hgv router. Now they have sent the new 2701HGV-C unit to run ADSL2/CN21 BB I can't get the **bleep** thing to open any ports for the static IP's and therefore my mail server and FTP servers are blocked from the outside world. I can't even turn the Firewall off ! I'm using the VOIP function on this router - otherwise I would dump it and get myself a Draytek.

I've re-installed my old 2700HGV and all back up and running - obviously there is a fault with the 2701HGV-C !!!