Assigning REAL IP addresses

[Barnacle]

I was told by our ISP that if I changed the subnet mask on our external address in our Cisco router to 255.255.255.248 from 255.255.255.252 we would have more external ip addresses available.

Does this apply to any devices plugged into our switches? Do I just give the device a static ip that is in the range of the new addresses that will be available, after changing the subnet mask? I would like to add a Snapgear VPN device.

Our current setup is Internet>Router>Server.

 

[ChrisAC]

A /29 IP range will give you six usable IP addresses where as a /30 (255.255.255.252) only gives you two. However, just changing the network mask on your existing IP won't do it. You have to use a /29 IP range that has been assigned to you by your ISP and that is routed to your router from the ISP's network.

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************

 

[Barnacle]

I believe that the ISP is already routing those IP's to us. How can I tell for sure?

The ISP's comment was "All you should have to do
is to change the subnet mask on the host addresses".

If are available, how do I make them "usable"?

 

[ChrisAC]

Confirm with your ISP the exact IP range and that they have pointed a route for this range down to your site. You can then configure the router and test it.

Chris.


**********************
Chris Andrew, CCNA, CCSA
chris@iproute.co.uk
**********************