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Confusion over the static ip address option


I am a little confused over the option of static IP with BT Business Broadband. When the 5 address option is selected I am looking to be able to set up a DMZ to host publicly accessible servers separate from the internal LAN not assign the internal devices with the assigned addresses. If I want to access an internal device I would do it via port forwarding as this would always be planned rather than ad hoc.


Having purchased 5 address static IPs what address is assigned to the WAN Port. The 29 bit mask suggested is for 8 addresses, take off the top and bottom address leaves one, is that the external address and is that still DHCP assigned by the BT Network.


The SON Guide includes significant help with SBS 2003 setup however this is somewhat out of date and I am trying to configure a SBS2011 network. This no longer uses a dual homed server with ISA and particularly does not like not being the DHCP Server for its network. It also causes lots of problems with the CA server if I change the SBS address so the internal network needs to remain on


As I am not ready to set up the DMZ do I leave the router to get its WAN IP address (I have turned off DHCP) and set up port forwarding to allow me access to the SBS server from the internet.


When I am ready to set up the DMZ can I isolate one of the router network ports to be on the subnet hosting the assigned addresses or do I have to create a VLAN. Although driven in part by the client OS this is really a router config issue. Is this beyond the capabilities of the BT Business Router?



Hi HairyFool,

Not sure if this is of help:-

1> Don't know what router you are using but if it is the BT Router there is a field under the Broadband> settings>add additional network > router settings> router address field for adding the public router address

2>SBS 2011 install differs greatly from earlier versions as does the RWA (remote web access)

Requirements for BT to set up via DNS Forms at  (or you via management of DNS Space)

New DNS A record,remote,the address of the router ie remote 

Create Sub domain off of your primary domain ie remote.hairy fool

You will need to also set up an MX mail record for the Exchange server MX

Strongly recommend you ONLY have 1 NIC in the SBS server for install

You don't need to enable VPN to access your local network

Should connect via https://remote fine providing the port fowarding is enabled on the bt router and the following ports are open 25,80,443,995 on both the server and internet router

If you use a managed hub/firewall between the server and the internet router then you can set up a DMZ on this at a later date







Thanks, usefull, especially the dnsforms bit, something I will look into.


Spoke to BT just now and lo and behold there has been a problem with their systemsSmiley Very Happy and the configuration change has not completed (although the order hasSmiley Sad).


Broadband link has been dropping intermittently last night and several times today and the external address has changed from 217.x.x.x to 81.x.x.x overnight and outside our allocated range so still not static.


As usual time is of the essence so I will set up the link via the IP Address or the hosts file initially once I can get the external locked. Don't really want to go down the DynDNS route if I can avoid it.