Hello, we're pretty new to IP addressing, my company siged up for a mlppp or t3, so we're trying to migrate over our current network from the old ISP, our plan was to keep the current IP addresses of 208.36.7.xx and nat that with the new IP block from ATT (12.54.120.xx for servers), we have a Netscreen25 f/w. We also have VOIP system.
We were tried setting the old ip's on the f/w trust port and then using the gateway ip from ATT (untrust), it wouldn't let us use the old block, it only somehow works with private addresses. So we're trying to look at some options, should we use new IP's from ATT to change all the servers addresses, or will we be able to keep our old IP's to use with ATT's new ip's. Thanks in advanced.