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New Member

Getting a new IP range from my ISP

I am getting a larger range of IPs from my ISP. Unfortunately, they are not within the range that I have now but they will be coming in from the same T1 connection.

I have numerous statically maped address to web and ftp servers. I can't statically map two outside addresses to a single DMZ address. So how can I make a smooth transition from the old IPs to the new? I would like to have both up for a week to give my DNS records a change to expire before cutting off the old subnet.

Any body have any ideas?



  • VPN
New Member

Re: Getting a new IP range from my ISP


I would suggest you create another Outside VLAN/interface on your firewall and put the new address space on that.

Then create secondary IP addresses on your web and FTP servers and create new NAT mapping for those on your firewall.

You might get problems with servers that don't allow secondary IP addresses on the same range as the original, in which case you would have to create another DMZ interface on your firewall and either use secondary addresses on the servers or add additional NIC (network interface card) hardware on them and configure them on the new DMZ. Then you should be able to accommodate requests from outside before and after DNS records get updated.