I am with three providers:
My domain registrar is GoDaddy. My webhost is HostGator. My business domain email is on Google Apps.
If my webhost goes down at any time (DNS) will my business domain email still be accessible on Google for sending and receiving emails (MX)?
So I guess my question is: do DNS and MX need to rely on each other, if one breaks the other will follow, or can they work separately? It sounds like I will always need GoDaddy's services to be "online" for either of these two things to work at all, is that correct?
Just trying to get an understanding of how things work when it comes to business domain emails through Google Apps when things go wrong on the web host portion of things.
If your DNS goes offline then your email and web traffic will also begin to go offline. Most people retain DNS with their registrar unless they have a specific need that would require it to be also served by their host. Web hosting servers and DNS servers are separate machines, DNS servers are generally a lot more resilient than webservers and are unlikely to go offline at any competent registrar or host, and typically will have multiple redundancy. Web servers at cheap hosting companies will have a lot higher downtime but this shouldn't affect DNS resolution and hence email deliverability.