Do I need to have DHCP enabled to use static IP addresses on the BTHub3?

[andyt22]

I have a BT Infinity for business connection with 8 static IP addresses and a BTHub3, and I have 3 servers already configured with public IP addresses. However, I have found that I need to have the BTHub3's DHCP server enabled in order to use the static addresses even though servers are already statically configured to use those addresses - if I disable the DHCP server on the hub, I lose connectivity for the static addresses. Is this normal?

I was hoping to disable the BT3hub's DHCP server as I already have another DHCP server on the same internal LAN; this is because I have two other broadband connections feeding into this LAN (Pipex business ADSL and Virgin Media domestic cable) and the existing DHCP server routes domestic LAN traffic via the Virgin connection. I want to use the BT Infinity connection just for business servers but sharing the same internal LAN as everything else in the house, without having to go to the trouble of installing a separate LAN.

Or is this dependency of static IP addresses on the DHCP server a limitation of the BTHub3 that's the reason others in this forum are buying Vigor and Draytek routers for use with Infinity?

Andy

[btnotverygood]

That is because BT does not offer REAL static IP addresses. They sell DHCP addresses with a long lease as a Static IP. No other ISP would dream of trying to get away with doing that. It amounts to fraud but based on my past experience with BT it is of no surprise. 

[DaveA]

Hi,

---

@btnotverygood wrote:

That is because BT does not offer REAL static IP addresses. They sell DHCP addresses with a long lease as a Static IP. No other ISP would dream of trying to get away with doing that. It amounts to fraud but based on my past experience with BT it is of no surprise. 

---

And your proof of this is?

Dave

[andyt22]

BY Infinity seems to use a form of super-nettjng where an ordinary dynamic IP address is used to route the static IP address block allocated to you through to your LAN. So you get your 8 static IP addresses (5 of which are usable for hosts) plus a dynamic one that can be used by other Nat's equipment on you LAN. It does seem unusual at first sight but this arrangement is sometimes done on Ethernet feeds in co-location data centres, for example.

But I don't regard it as a fraud - the static IP addresses are real enough and I have to say I'm very pleased with the service.

Andy

[Stephenc]

Hi Andy,

You should be able to disable the DHCP server on the hub.  Make sure the default gateway for the range has been specified under static ip tab.

Once this has been done, under business network - ip addresses.  Disable DHCP.

You would then need to statically assign your ip addresses on the tcp/ip settings of the connected device.

IP address: one of the five you have in the range.

Subnet Mask:255.255.255.0

Default Gateway:  The ip address one greater than the address of your range.

Then open any ports required.  If you are losing connectivity when this is disabled, you could try this with one machine, with the server etc temporarily disconnected, if you're still not getting connecrivity, I'd call the tech desk to get this checked.

Thanks,

Steve

[andyt22]

Thanks for the info, Stephen. I'll try as you suggest next week when I'm back at base.

cheers, Andy