Domain Name System – DNS for short, is something that practically everyone is familiar with, but doesn’t always realize. What is DNS responsible for? Its job is to translate domain names as understood by humans (e.g. smarthost.eu) to an IP address. This is quite a convenience for us, because we do not have to remember numbers, e.g. 193.93.88.166, and we only need the text address itself.

DNS operating principle

In a nutshell:
When we want to access smarthost.eu, our system asks the DNS server it knows: “hey, do you happen to know the address for the smarthost.eu domain?”. The DNS server replies: “Yes, I know it! Its address is 193.93.88.166.” After getting the answer, we can connect to our desired site.

The domain system, is a hierarchical system where, for example, “.pl” – is the domain assigned for our country. Within this domain there are sub-domains, such as regional domains (czest.pl, lodz.pl, etc.).

Each of the main domains is supervised by an organization that is responsible for the supervision and administration of the granting of names. In Poland, such an organization is the Scientific and Academic Computer Network (NASK) .

There are two types of DNS servers. Recursive servers, whose mission is to find the IP address of a given domain. And Authoritative servers, which store the configuration of domains. Their only function is to respond to queries from other name servers.

Time to Live

TTL (Time To Live) – is a parameter that determines the lifetime of a packet or other data (such as a DNS record). In the case of DNS, it means exactly the validity time of DNS settings, i.e. the time that passes from one setting update to another. By default, many web hosts/providers set this time to 48 hours. The question at this point begs itself – why? I’m already answering: because to increase the speed of opening websites and reduce data transfer.

How does it work in practice?

When we want to delegate a domain to other DNS servers (e.g. dns.smarthost.eu, dns2.smarthost.eu) your request will be updated according to the TTL time set. In case your current domain hosting provider has the TTL time set to 24 hours, this will be forwarded to other registries within 24 hours (unless we are lucky and hit e.g. 5 minutes before the update). Therefore, before delegating the domain, we recommend reducing the TTL. Then the IP address of the domain, is further propagated on the Internet. Among some servers faster (TTL, e.g. 5 minutes), and among others longer (e.g. 36 hours).

Therefore, the propagation time can be up to 72 hours.

Operations on domains

There are several of the most common operations related to domains. Delegation, entry changes or domain transfer are the daily bread for our administrators. However, when we want to perform such operations, it would be worthwhile to familiarize ourselves with what principle they work on.

Domain transfer

A domain transfer involves moving from one domain hosting company to another. For this operation you need an AuthInfo code, which you need to obtain by contacting the original hosting company. Most often, the registrar requires you to fill out an AuthInfo code request and send a scan/photo of your ID with sensitive personal information covered. Once you have obtained the desired code, you can start the migration process. If you want to transfer your domain to Smarthost be sure to read the free website transfer guidelines.

Sometimes it happens that you need to change your domain service company to another one, where both operate within the same operator/registrar. In such a situation, you will need an e-assignment code.

Domain delegation

We use domain delegation when we do not want to change the registrar, and we have hosting elsewhere, and our domain is to use it. You should then point to our DNS servers:
dns.smarthost.eu (91.211.220.10)
dns2.smarthost.eu (193.93.88.10)
dns3.smarthost.eu (51.91.27.195)

When delegating a domain, keep in mind the DNS propagation time, related to TTL, as I described above.

Operations on entries

This is already an option for more advanced users. The description of domains is done with the help of so-called DNS records. Among the most popular of these are:

• SOA – informs that a particular server is the best source to derive domain information. It also defines the behavior of Primary and Secondary servers. SOA is the first record in each file containing records (the so-called zone file)
• A – IPv4 address
• AAAA – IPv6 address
• MX – mail server address. It specifies the name of the computer that is the email server.
• NS – the address of the DNS server for our domain.
• TXT – text record, allows you to enter any text. Mainly used to fight spam by the SPF service.
• SRV – the so-called service record. It contains data about the location of our service to which the DNS server points. Often used with various VoIP services (such as TeamSpeak) or protocols.