Which IP address is used to point a domain name from a registar to a host : the main virtual IP address or the server's IP ?

it will depend on your domain is base on shared IP or dedicated IP. It best that you check with your host and their should be able to provide you. Or you can provide me your domain and I will point the IP out for you

Your hosting company will tell you the ip address to point your domain to.

The IP used in your server's httpd.conf (Apache configuration file) for your domain.

What scenario are we talking about here?

Is it a case of the registrar hosting the DNS, and needing to point the A record at a hosting company's web server?

Or is it a case of the registrar merely registering the domain and the hosting company hosting the DNS?

Without knowing who is hosting what there is no way of answering the OP's question!

What scenario are we talking about here?

Is it a case of the registrar hosting the DNS, and needing to point the A record at a hosting company's web server?

Or is it a case of the registrar merely registering the domain and the hosting company hosting the DNS?

Without knowing who is hosting what there is no way of answering the OP's question!

Lubeca, with all due respect, I don't see a difference who's nameservers are used: registrar's or hosting companie's. In any case, in order to serve a webcontent, domain's A record should be pointed to the IP Apache is listening to for that particular domain.

Lubeca, with all due respect, I don't see a difference who's nameservers are used: registrar's or hosting companie's. In any case, in order to serve a webcontent, domain's A record should be pointed to the IP Apache is listening to for that particular domain.

Yes, someone will need to point the A record to the web server. That goes without saying.

But to answer the OP's question we need to know if he has an all-in hosting package with the company that hosts his web site, or whether the DNS is hosted by the registrar.

If the OP has an all-in hosting package with the company that hosts his web site then the hosting company will set up the zone files and the registrar needs to be told what name servers to delegate the domain to.

If, on the other hand, the registrar hosts the DNS (a service which more and more registrars now seem to offer) then the registrar will be setting up the zone files and the registrar will need to be told the IP address of the web server.

The question the OP seemed to be asking was "What information do I give my registrar" - and the answer to that depends on who hosts the DNS, i.e., registrar or hosting company.