hi

First off - sorry if what i'm about to say it totally wrong....

What i'm after, is having 2 servers, and if server 1 goes down, everything is directed to server 2. (server 2 being a backup system only)

Server 2 would be mirrored in web files etc

Does this work by setting the ns2 DNS to the IP of server 2?

Ie,
ns1.domain.name -> server 1's IP
ns2.domain.name -> server 2's IP

What i'm trying to ask, is, does DNS work in the same way as MX records, in that if the 1st one is available, it goes to the 2nd MX record?

that make sence!?!

It makes sense, but unfortunately, it can't do what you are asking for (it's not the same as mx records). If you need one server to take over if the other goes down, you need some sort of load balancer whereby if one server goes offline, it will redirect all requests to the other server.

Alternatively, if you want to do it manually, you can configure your DNS settings with a very short TTL so that the IP of your main server does not hang around in cache for very long. If that server goes down, you then change the DNS A record to the other server.

dnsmadeeasy.com can offer this service to, check out http://www.dnsmadeeasy.com/s0306/prod/dnsfo.html.

Or you can do round robin DNS, in which case you stick both IP's in for the same record, both will be returned to the client, and then you hope the client picks the IP that is not down at the time for the one to connect to, i don't know about others, but FireFox cycles through all the IP's it gets IIRC.

A DNS client will pick an address at random if there are multiple A records for a given host. However, if a server goes down, half your clients will end up on the "down" server, so as a backup solution, round robin is no good. It's great as a simple load balancing system if you keep the two servers synched though.

thanks for the advice

didn't think it would be an easy option.... looking at 'DNS made easy' option.... just not sure how Helm would work, being as the DNS wouldn't be hosted on the box itself!?

Helm would work, it just wouldn't control your DNS servers anymore effectively.