topic BT BH3 - Static IP BT to BT Nat issues! in Archive

BT BH3 - Static IP BT to BT Nat issues!

notmeagain — Fri, 25 May 2012 22:56:17 GMT

Hi everybody,

I've recently upgraded to the BT Business package for their multiple IP addresses and the ability to run a server on the line.

My setup is this:

BT Hub, with BT Static IP enabled.

One of the range is assigned to my Windows Server 2008 machine through the routers "Allways use this IP" as per the online help.

Port forwarding has set up to allow access to the software (a game server), and directed to the Server2008 machine, as per the instructions online.

With the firewall set to allow access (Default), some clients can connect, yet people who are using BT are getting nat negotiation failure messages.

This only seems to affect BT customers at this time.

Other symptoms to note:

Without the port forwarding I am still able to connect via remote desktop to the external IP, this is wrong.

Also without port forwarding I am still able to connect to the game server using the external IP.

Can I get some assistance please?

feel free to call me, you have my contact details!

Re: BT BH3 - Static IP BT to BT Nat issues!

kimura — Sat, 26 May 2012 17:07:25 GMT

Hi. Are these servers assigned by a public or private IPs? They need to have private IPs assigned.

The idea of port fowarding is to make nodes with private IPs reachable through port forwarding, otherwise known as NAT. You might want to check out this link too.

http://btbusiness.custhelp.com/app/answers/detail/a_id/9445/~/how-do-i-set-up-port-forwarding-on-the-bt-business-hub%3F

Re: BT BH3 - Static IP BT to BT Nat issues!

notmeagain — Sat, 26 May 2012 19:05:41 GMT

The guide here does not dictate having internal ip addresses as necessary.

http://btbusiness.custhelp.com/app/answers/detail/a_id/19138/c/426,3671,3838

It suggests allowing the server to obtain the ip address through DHCP and assigning the static ip address through the router as displayed, and then port forwarding as required.

Is this not the correct method?

Re: BT BH3 - Static IP BT to BT Nat issues!

notmeagain — Tue, 29 May 2012 00:09:47 GMT

So, it appears that if i access the device "FIRST" ie: after it's just restarted, other people cannot connect over the public ip.

If i access the device after a few people have connected, everything is fine.

It appears to be an issue with the way the business hub handles the mapping of the external ip address.

Normally, and in almost EVERY OTHER router, you cannot and will never be able to access something on the lan that is of a differing subnet.

EG:

Me IP assigned via dhcp: 192.168.1.66

Server IP assigned via dhcp: 88.22.11.44

I should not be able to see the server on the lan with that IP address.

I should not be able to access that server on the lan with that ip address.

But somehow I can :D.

I temporarily replaced the BTBusiness hub with an installation of Smoothwall express 3sp2 - and this handled perfectly as expected, but this was with IP Aliasing, the Business Hub is not really a Business grade product, but more of an "Advanced" residential router.

But for a free bit of kit I shouldn't complain.