What is the difference between using the DNS at my registrar, and using the DNS of the company that is hosting my server?

Let me explain: my registrar is register.com and, if I use their name servers, they allow me to add CNAME, A and MX records for my sites.

On the other hand, if I point the register.com name servers to the DNS servers provided by my hosting company, then I can change those same DNS records through a user interface that my hosting company provides.

As I see it, these are two ways to do the same thing. So I ask what am I missing? Why would I want to use my hosting company's DNS servers instead of those of register.com? Or vice versa?

From what you are explaining, if you can modify records at both your registrar and host then the only difference is where the nameservers are. Sometimes your host will give you branded dns, not sure what registrar's is.

Regards,

Mike

You could use them both for redundancy.

Originally posted by Racin' Rob
You could use them both for redundancy.

That thought has crossed my mind. I am thinking about the added complexity of maintaining the DNS records on two sites (high) vs. the need I have for redundancy (low).

The registrar's name servers are _probably_ more reliable than your web host's. Moreover, your registrar's name servers are more likely to be actually run on different physical machines, as opposed to the practice of lots of the smaller web hosts of running two nameservers on two ips on the same machine. Registrars' nameservers _may_ also keep more up to date with security issues than small web hosts' nameservers. All of these may contribute to additional redundancy/reliability.

Your registrar's name servers will probably be more of a hassle to update, and may not update quickly. I don't know about register.com, but enom's nameservers are not updated immediately or in real time after you make changes. This is not due to dns propagation/caching - I queried enom's nameservers directly. If you go with your host's name servers instead they _might_ be updated immediately after you make changes.

Because of the uncertain amount of time involved for changes made to your zone at your registrar's nameservers to be made visible, it may not be advisable to use both your registrar's nameservers and your host's nameservers (if this is possible at all, that is - enom doesn't allow this). Some users - those querying your registrar's nameservers - may receive different results from those querying your host's nameservers if you've made changes to that record. This difference may last for up to 1-2 days, during which time it can be quite difficult to troubleshoot exactly what's going on (but now that you know, you can just tell everyone that it's a temporary problem).

Redundancy of name service is of questionable use anyway. If the only records in your zone are hosted with your web hosting company, you're unlikely to benefit from being able to resolve names if your web hosting company is down/unavailable.