Forum Discussion
Nick_T_68319
Nimbostratus
NimbostratusGlobal Name Server placement
I have 3 datacenters, two in the united states and one in the UK. I'm adding another pair of GTM's to the UK datacenter shortly, so there will be 6 GTM's in my sync group. My question is, curently on all of our domain's, we basically have NS1 and NS2 listed, the two US datacenters. I want to add NS3 for the UK datacenter. However, how are the name servers selected when a client looks up a DNS record? I see mixed information online, is it random? 1st, 2nd, 3rd? Will it create an issue by adding a UK name server with latency for US web sites on DNS lookups? Thoughts?
4 Replies
Nick_T_68319Just doing some research, it doesn't sound like there is a clear cut answer. A lot of it is "it depends" I've seen:
1) Clients query all name servers and whatever once responds first wins
2) Clients go to the first, then second, then third
3) Random
What has everyone else experienced?- Laudec_55181
Altostratus
Having more than one name server (a DNS record type) set to your domain name provides redundancy, and works for ensuring your website's availability at all times. If, for some reason, your primary name server cannot be reached at a given time, your visitor's DNS resolution request is routed to the secondary server set for your domain. If, however, this one is unreachable too, the request is routed down the whole chain of name servers until the requested IP address matching the domain name your visitor types in the address bar is located by the DNS server. - Nick_T_68319Correct, so if that is the case for my UK sites, should i put NS3 (UK DC) listed first under the registrar? That way the first name resolution isn't going to the slightly higher latency US name servers for a lookup?
JGCumulonimbus
As I understand it, the NS records you registered with an Internet Registrar are just glue records, which lead the user to your name servers. It is up to the local DNS server which of these ns1 and ns2 records to use to get to one of your name servers. From our access stats here, the first one listed gets used more. Then your name server can serve its own set of ns records, usually the same as those with the Internet Registrar, but they can be different. This is where you can configure how/where to send the records according to your deployment stragegy, topology for an example.
The short answer seems to be: Yes, you can add the 3rd NS to your NS list with the IR, but you need to configure your GTMs redirect requests to the DC closest to your user.
Let me know if this makes sense to you. I myself are planning a similar deployment at the moment.
