Setting up router for internet connection

[nicholab]

BT have said that we have a wan IP address with 255.2555.2555.254 netmask and then are public range should be on the other interface. I have always seen a site router take the 1st usable ip address in the public range so I am a bit confused how to set this up?

[Dos_Box]

The router is in effect, your link to the outside world. As long as your server/firewall/utm are configured to see that, then that will be all you need if your system is configured to use it as your gateway. You can then use internal IP addressing for all other clients and servers.

Looking at the configuration you have shown, you will only have the one public IP address, and TBH, that will be all you need as long as the internal systems are configured correctly to use it for external access.

[Dos_Box]

Quick question? Is the IP address you have been given outside of the internal ranges of:

 

10.x.x.x

172.16.x.x

192.168.x.x

 

?

[nicholab]

Yes it is outside of the range of private ranges. If i give one of the ip address to another interface of the router I can ping it from the internet.

[Dos_Box]

OK. Does your router have 2 (or more) interfaces? If so, give the external interface the public IP and the other an internal IP so your systems can 'see' it. One gets connected to the outside line and the other connects to your switches/UTM/Servers (depending on setup).

Do you have a firewall/filtering box or UTM? If you can give the make/model of the router that would be helpful.

[nicholab]

I want to do every thing on a Cisco 1941 router. I want to assign the public IP's to four NAT block corresponding to the different vlans. Before the router WAN address was one of the public block now BT are saying this is not so.

[Dos_Box]

So, let me get this straight. You have been given a router by BT, and a public IP address to go with it? How is teh router connected to the internet? ADSL, a CAT5 connection perhaps?

If it is CAT5 you could try giving that IP to your Cisco and seeing is you can connect it that way. It may also be that the BT router is hardwired into their internet setup and trying to use anything else won't work.

Could you give us some more details please such as connection type/speed and contract (business. education etc.) as well as the make/model of the BT router as this will help a lot in trying to find out the correct course of action?

[nicholab]

It is a BTNet fiber business connection no router option it is our router BT have set it up differently after migration and they will not say what they have done.

 

BT is email says

 

Pop 109.x.x.x 255.255.255.254

Site router wan 109.x.x.x 255.255.255.254

 

Customer lan 62.x.x.x 255.255.255.240

 

The difficult think is that we use private address in our LAN if it we did not we could give each work station a public address. I need to give the NAT pool addressing in the 62.x.x.x. 255.255.255.240 space.

[Dos_Box]

So BT have altered your router and not told you what they have done (where you there when they did it?) and now you cannot get internet access?

Why have they given you a public IP range for your LAN as well? Seems a bit bafflling to me :/

 

Looking at the IP ranges you have been given I would say the WAN address is your external IP address, which is fine. However can't you reconfigure your router to simply use that and carry on using your internal range?

[EduTech]

Yup,

 

FE0/0 will be your /31 subnet and then FE0/1 will be your /28 subnet.

 

You will configure your firewall external interface, gateway being your FE0/1 IP Addreess and then you will have your Internal Interface which will have an IP which will be used as your Gateway locally.

 

I think that should help,

 

James.

 

FYI - I have just had a BT Net Fibre Connection Installed 10/100 Circuit. :-) I have 2 Routers and a Firewall though as I have one being a VPN Router (not a EDU network).

 

The 2 public ranges are correct.

Edited September 28, 2011 by EduTech

[Dos_Box]

So:

 

WAN (external)- 109.x.x.x 255.255.255.254

Gateway (internal)- 62.x.x.x 255.255.255.240

 

She would use the gateway IP to route through to the WAN? Thanks James, it's a bit clearer now

[EduTech]

Example:

 

Physical Connection Inplace: BT Fibre Panel RJ45 Connection > FE0/0 Cisco Router (CrossOver Cable)

 

FE0/0 Configuration

 

109.xxx.xxx.xxx /31

 

FE0/1 Configuration:

 

195.xxx.xxx.xxx /28

 

Physcial Connection Inplace: FE0/1 Connect to Port X on Firewall

 

External Interface: 195.xxx.xxx.xxx /28

 

Physcial Connection Inplace: Internal Interface Port X on Firewall > Internal Network

 

Internal Interface: PRIVATE ADDRESS?

 

I think that is pretty much the scenario you would have.

 

James.

Edited September 28, 2011 by EduTech

[nicholab]

Think is this used to be done on one router I don't want to start using two routers.

[EduTech]

Think is this used to be done on one router I don't want to start using two routers.

 

You don't need 2 routers, you only need 1 router.

 

1x Router and 1x Firewall Device

 

James.

[nicholab]

Before this could all be done on a 1941 router firewall and routing.

[EduTech]

so before did you have Fibre Panel > Router / Firewall?

 

If the setup you have currently no longer works due to them changing something then i guess you speak with BT, have you upgradeded your connection or something?

 

James.

[Dos_Box]

James, have you looked up the device they are using?

 

 

 

 

Nichola, is this the Cisco 1941 you have (there are several varients you see)?

[EduTech]

James, have you looked up the device they are using?

 

I did after that last post, but yeah found different versions...

 

Let us know what version, maybe able to spread some more light..

 

J

[nicholab]

Yep that the one 1941w we used to give the router the 1st public ip address and Nat some of the other using the router. Edited September 28, 2011 by nicholab

[EduTech]

Okay, so at the moment does your GE0/0 go to Fibre Panel (CrossOver Cable)

 

Do you have any WIC Cards in your router or does it just come standard:

 

http://sevenlayers.files.wordpress.com/2011/02/1900.jpg

 

 

James.

[nicholab]

GE0/1 goes to BT fibre panel.

[EduTech]

GE0/1 goes to BT fibre panel.

 

Ok, It is my understanding that the fibre panel will be configured for the /31 address.

 

But I don't understand your scenario,

 

Did this used to work and just stopped working today? or/ have you had some work carried out? or/ is this a new install.

 

I ask this because BT sent me a beast out when I had mine installed, I aint using it as i needed to be able to access thr router but they had the same setup as i had now /31 on the GE0/0 and then /28 (mine was a /29) on the FE 0/1

 

So, what has happened for all this to change in your environment?

 

James.

 

P.S. PM me your telephone number or/ IM Address if you want and we can talk easier..

[nicholab]

Layout

 

POP

|

Router

|

Public address

|

NATed addresses

[nicholab]

The solution to this problem is BT WAN network address goes on as the secondary ip address and your public ip go on as the Primary IP. This is different between a 100mb vs 10mb bearer. Hope this helps anyone else.

[EduTech]

I am pleased to hear you managed to get this sorted mate, My setup was based on a 10/100 Ciruit (100Mbit Bearer).

 

James.