We're going to be transitioning from Verizon to AT&T and we want to run them in tandem for a week or two. We're trying to avoid an interruption in service to our web and email servers. We want the Verizon link to answer up and resolve names while the AT&T dns info propagates out across the web.
I'm asking for an overview on the setup of routing and dns for
redundant ISP connections. We own the routers, Verizon and AT&T manage them.
Verizon uses a Cisco 3600, AT&T it's a Cisco and it's a later model than the 3600 not sure just yet.
We maintain the primary DNS server in house, running Bind 8.2, Verizon and AT&T maintain the secondaries. Network Solutions is our registar there is something thats setup there that points to the name servers.
Checkpoint R60 does the Nat'ing for us. I'm using Static or one to one nat.
Quesitons on DNS - Can you have both sets of secondary servers in the Allow Transfer On line in the named.conf file?
What do you do in the zone files? I currently have Verizons public ip addresses assigned to us setup as the A records in the zone files. Can I simply add the AT&T public ip addresses in the zone file?