nameserver help

[PaullasPaullas is verified member.]

Can anyone tell me if i am right in thinking if i setup the below nameservers will work.

if i have the following nameservers setup on a domain name

ns1.domain.co.uk (hosting 1)
ns2.domain.co.uk (hosting 1)
ns3.otherdomain.co.uk (hosting 2)
ns4.otherdomain.co.uk (hosting 2)

so in effect if the hosting 1 goes offline then the hosting 2 nameservers kick in and the backup sites will come online.

Is the above right or if not can anyone explain the best way to do this please.

thanks in advance.

 

[PoshTiger]

It is correct, but is it not better to have these as the primary / secondary

ns1.domain.co.uk (hosting 1)
ns3.otherdomain.co.uk (hosting 2)

And these as a backup

ns2.domain.co.uk (hosting 1)
ns4.otherdomain.co.uk (hosting 2)

As long as the zones are all correctly setup and transfer successfully between themselves, it should work fine.

The order will only come into play if there's a total loss of hosting1.

 

[PaullasPaullas is verified member.]

thanks for the reply. so would you reccommend i leave ns1 and ns2 and if the hosting goes down i manually change to new nameservers until main hosting is back online.

 

[PoshTiger]

Well a nameserver change can take 48 hours to propagate throughout the whole internet so you may get quite a bit of downtime if hosting1 totally fails.

Are the servers at hosting1 configured to transfer their zones to servers at hosting2 automatically?

If they are, I'd put both hosting1 & hosting2 nameservers in the mix somewhere.

 

[tifosi]

thanks for the reply. so would you reccommend i leave ns1 and ns2 and if the hosting goes down i manually change to new nameservers until main hosting is back online.

If your hosting goes down no amount or configuration of nameservers will help!!

 

[PaullasPaullas is verified member.]

If your hosting goes down no amount or configuration of nameservers will help!!

I know that hence ask for advice on automatically or manually changing name servers is the best way to go.

 

[tifosi]

Really depends if you're relying on the hosting companies dns servers or your own servers caching nameservers ties to glue records on your domain.

There's always a risk with caching nameservers with having them on your servers ips i.e. on the same c subnet range.

server ip 123.456.7.8
domain abc.tld
nameserver1 ns1.abc.tld 123.456.7.8
nameserver1 ns2.abc.tld 123.456.7.9

If your server goes down the nameservers go with it. So having the nameservers split across 2 subnet ranges is better. But if your server goes down. The site still won't resolve.

You don't 'need' nameserver based on another domain. If you're not using custom nameservers then just use your hosting companies dedicated ones, otherwise set up your 2-3 custom nameservers across 2 subnet ranges.

Because of propogation times/delays swapping and chaging nameservers really isn't an option. Set them up when the server/vps is set up and then leave them. Unless you're actively moving the domain of course.

 

[PaullasPaullas is verified member.]

Really depends if you're relying on the hosting companies dns servers or your own servers caching nameservers ties to glue records on your domain.

There's always a risk with caching nameservers with having them on your servers ips i.e. on the same c subnet range.

server ip 123.456.7.8
domain abc.tld
nameserver1 ns1.abc.tld 123.456.7.8
nameserver1 ns2.abc.tld 123.456.7.9

If your server goes down the nameservers go with it. So having the nameservers split across 2 subnet ranges is better. But if your server goes down. The site still won't resolve.

You don't 'need' nameserver based on another domain. If you're not using custom nameservers then just use your hosting companies dedicated ones, otherwise set up your 2-3 custom nameservers across 2 subnet ranges.

cheers. i am in discussions with them at the moment so will point the above out to them

thanks again

 

[sdsinc]

It is recommended to have consistent DNS configuration for all your name servers.
Essentially, it's like a load balancing setup.

So use your four name servers and add the two IP addresses for your server (you possibly have even more):
ns1.domain.co.uk
ns2.domain.co.uk
ns3.domain.co.uk
ns4.domain.co.uk

DNS records:
A <IP hosting1 IPv4>
A <IP hosting2 IPv4>

You may also add AAAA records if you have IPv6 addresses.

There is no way to predict certain name servers in your set will be preferred to others, this is unlike MX records where you can set the distance (preference) but no guarantee clients will abide by it.
However, if the first IP address is unreachable the client will normally move to the next one, and so on.

 

[jimm]

As mentioned if its in DNS its live. The 'backup' site is effectively live.
But you cant change the DNS when the hosting goes down as it will take too long to actually come into effect.
High availability can not be done at DNS level reliably.