No Comments Written by Robert on April 11, 2008 – 4:55 pm

I’ll write a short introduction on Internet Protocol (IP) addressing and the Domain Name System (DNS). The material on DNS is probably new to some of us.

IP addressing is still mostly based on the IP-v4 protocol.With IPv4, each machine actually connected to the Internet is identified by a 32-bit bit-pattern (IPv6 will increase this to 128 bits). Client machines used for browsers and so forth can have their IP addresses allocated on a per-session basis. Your Internet Service Provider – ISP – probably has a stock of a few thousand IP addresses; your machine is allocated one when you dial in, and this IP address gets reallocated after you disconnect. Sometimes your ISP may even change the IP address that you are using during the course of your session. However, servers obviously require fixed IP addresses – their addresses need to be made known to customers and so cannot be changing all the time.

You would not want to publish an IP address for your server; you want it to have a memorable name that will in itself attract customers. Your server name has to be registered with the Internet system before clients can use it to reach your services. A server name comprises a machine name and a domain name, and both must be known to other machines on the Internet.

Getting a domain name for your host machine(s) is relatively easy; you just have to pay an organization like Network Solutions. The rest involves rather more work. Your company is going to have to run programs that support the domain naming system; these programs are going to have to deal with requests for the actual IP addresses of machines in your company’s domain. (Actually, it is probably better for a really small company to offload this network administration work to a service company, but eventually a growing company will need to control its own domain). You as an individual are unlikely to become responsible for your company’s DNS system for quite a while. But eventually you will get that responsibility. Meantime, you do need at least a limited understanding of the mechanisms that do the mapping from domain names to IP addresses.

I promise to continue with this later on.