DNS: Can one name resolve to 2 IP addresses?

[Plater]

Here my situation:

My company network has 2 connections externally ( A T1 and buisness cable).
Each have static IP addresses.
We have a dual WAN router in place handling them.
that part seems to be fine.

My question then is, can we have our domainname (hosted externally by some register company) point to both IPs somehow?
We currently just have an A record for each external IP address. (wan1.example.com wan2.example.com)
We want www.example.com to try wan1 first and on a failure try wan2.
So if our T1 goes down, the same name can then route to our cable connection.

Is this possible? Or do we have to have our domain provider do something special for us?

[jehrich]

Hi Plater,

Some DNS providers offer specific failover services that monitor your connections and always respond to DNS queries with the IP of the working connection(s).

Even if they don't offer this they may still offer round-robin DNS. They basically set up two A records with the same hostname but different IP addresses. When somone requests the A record the DNS server responds with the next address in the pool, in your case alternating between the two addresses. If one of your connections becomes unavailable, the ~50% of users directed to the other IP will not notice. I believe that some implementations resopond with all addresses in the pool and leave the decision of which address to use up to the client.

Hope that helps.

JE

[Plater]

That is exactly the kind of thing I was looking for.
In a twist of events, we have dropped our T1 due to severe lack of reliability. So it's not even an issue anymore.
Good info for future use though.