Now, does a Web server need a static IP address to register to the DNS
server and point the location?
No, the web server does not need a static IP. There are essentially three basic parts to hosting a website:
- The registrar (which updates the information for your site name -- ex. www.mysite.com)
- The Domain Name System (DNS) Server (which helps translate your site name to an actual IP used by your web server)
- Your web server
For example, www.mysite.com may hypothetically need to be associated with the IP
220.127.116.11, the address assigned to your computer via your ISP. DNS is what does does this.
The DNS server address itself needs to be (relatively) static so it can be found, but as long as the DNS server has a record of the appropriate IP address of your computer, it can forward data to that server. You can think of it like delivering a letter -- the Post Office (DNS server) has to stay in one place to receive mail but it can send mail wherever it likes (no matter how much you move).
How would you configure the DNS to point to a dynamic IP address?
You need to have a system where the DNS records are updated to match the current IP address of your web server. This can be done manually or automatically, depending on circumstances and preference.
If your comfortable with DNS records and don't have an IP that changes often...
You can run a DNS server (such as BIND) yourself. While not generally difficult, you should be aware that there are potential complexity and security concerns with running your own DNS.
You can manually update a third party DNS provider such as xname.org. These services offer you a form to create DNS records that are loaded to DNS servers which are hosted for you. However, this process isn't automated. You have to manually change the IP of your web server every time your ISP updates it.
Both of the above can cause issues with availability if your IP changes and so may not always be a good solution -- but they are doable even with a "dynamic" IP, assuming your ISP doesn't provide a new IP every time you connect.
Since there is a market for less-than-technical people wanting domain names and DNS services, more and more automated services are being offered. These services often avoid most the of the hassles of DNS at the cost of some potential control of your DNS records.
Usually, a small program is downloaded to the web server which automatically keeps track of the web server's current IP as assigned by the ISP. This program, in turn, relays this information to a set of DNS servers, which are then automatically updated with the appropriate DNS records each time an IP address change is detected. Extending the first example given, it would be like hiring a butler to call the Post Office for you every time you moved so your mail could be forwarded appropriately.
Currently, there are generally two types of these services -- ones offered by DNS-only outfits such as No-IP and afraid.org and ones offered by domain registrars such as NameCheap.
With DNS-only dynamic IP services, you are usually allowed to choose a URL/subdomain that will point to your computer (e.g. mysite.dyndns.com). People can then use this domain to directly access your web server.
If you want to use a registered domain such as www.mysite.com, you either have to forward that domain to your dynamic subdomain (e.g mysite.dyndns.com) or go through special procedures to allow the dynamic DNS company to directly associate www.mysite.com with their (automatically updated) DNS servers.
If you are using a registrar that provides these services (again, such as NameCheap), this is not necessary. By default, when your register a domain name, the DNS servers associated with that domain name will be the registrar's. From there, all you need to do is download the dynamic DNS update program and everything should be automatically taken care of (e.g. www.mysite.com will be associated with your dynamic web server with no extra steps involved).
It's likely worth mentioning that NameCheap also has a FreeDNS service for existing domains. In short, what this means is that if your domain name is registered with a registrar that doesn't provide dynamic DNS, you can simply switch your existing domain's DNS to NameCheap (without actually being their customer) and take advantage of their dynamic DNS services.