Guide to DNS - DNS FAQ
A domain is a name that uniquely identifies a web space. The actual space is accessible via an IP address but, by convention, these numeric strings are associated with a name (the domain) that is easier to remember. The name of a domain is composed of two parts separated by a dot – the first (SLD) is the name, the second (TLD) is a suffix that indicates a national geographical area or the type of activity the space is used for.
TLD stands for Top Level Domain, i.e. it is the first-level domain. It is the suffix of the internet domains and can be generic (gTLD) or national (ccTLD).
For instance, the TLD of sitodiesempio.it is it
SLD stands for Second Level Domain. It is the prefix of the internet domains and, together with the TLD, forms the domain name.
For instance, the SLD of exampledomain.it is sitodiesempio
An IP (Internet Protocol) address is a unique numeric label that identifies each computer, server, network or device (or more generically host) connected to the internet and using the Internet Protocol as the communication protocol.
A nameserver is a DNS server dedicated to the resolution of IP addresses.
The nameservers are organised in a pyramid structure. When a computer requests the resolution of a domain name from the DNS system, the domain name is scanned from right to left, asking each nameserver to provide information only on the element that is to the left of the last dot.
The root nameservers are the servers with greatest responsibility (called authoritative servers, i.e. granted authority) and are located at the top of the pyramid. They hold the list of the servers responsible for each of the first-level domains recognised and provide server IDs in response to each request. Each first-level domain (e.g. .com) in turn owns a group of authoritative servers which in turn delegate some of their authority to the nameservers responsible for each second-level domain (e.g. nidoma.com).
These last respond to questions on IP addresses relating to subdomains or individual hosts (e.g. www.nidoma.com).
The Domain Name System is a system that has the function of converting the names of networked machines into IP addresses and vice versa.
Its function therefore allows reaching a web space starting from the domain name and not from the IP address.
DNS records provide instructions to DNS servers in order to establish a direct association between an IP address and a domain name. Different types of information correspond to different DNS names, and therefore there are different types of DNS record. The main types are:
- A Records: these records refer to the IP address associated with the domain.
- CNAME: records used to indicate subdomains associated with the main domain.
- MX: indicates to which server e-mails should be sent for a particular domain.
- NS: shows which are the name servers currently in use for a particular domain.
- SOA: this record contains important information about the domain, for example the last time it was updated, and related contact information.
- TXT: associate text fields with a domain, and can contain informative descriptions.
Domande Frequenti sui DNS
The domain is parked because when the recovery system takes over a domain, the Nidoma DNS are associated to it.
Only when we make the change of registrant (assigning it to a customer) are the DNS changed, entering those the customer has set up in the order.
Yes, when you get to the page "order domains"
- press the "to be configured" button;
- on the Domain settings page: in the "DNS configuration" tab choose "Use customized DNS set" and select the DNS;
- in the Apply configuration tab select the domain to apply this configuration to and press "Apply configuration".
In order to set new DNS, first you have to create a DNS profile with the Name Server that will be applied on domain.
- From the dashboard click on "domain management" and then on "DNS settings";
- click on the right-hand button: Add DNS profile;
enter the data and save.
In this case please contact us via email or contact form specifying the name servers that you want to set.
First create a
Now that the profile has been created it will be applied in the "domain management":
- click on "domain management" and then on "domain management" again;
- select the relevant checkbox;
- under "Options in bulk" choose the "DNS configuration settings" option and press Apply;
- change the DNS and save.
The Italian NIC has an internal verification test under which, once the DNS is changed, it updates the status of the domain to "pendingUpdate" and at the same time checks whether the new configuration is working.
If over the next three days it is not verified, i.e. if the DNS settings chosen are not considered correct, it is rejected and the domain goes back to the "ok" status.
There are more details on this topic in
However in this case it is advisable to contact your DNS provider to resolve the problem.
In order to change correctly the nameservers on your .IT domain, NS (NameServers) must be setup and resolve before updating the domain settings on control panel.
The NIC-IT (Italian Authority for the registration of domains with the .IT extension) performs checks on the NS (NameServers) of its own domains. The domain zone must be preconfigured with certain conditions on the NS themselves.
Before applying new DNS settings, the NIC-IT performs checks on the NS (NameServers). The following guidelines must be verified: The procedure for checking the nameservers analyses all the hosts to associate with the domain names registered in the Registry Database that are in inactive/dnsHold or pendingUpdate states and performs appropriate queries (i.e. requests to the nameservers) to verify their functioning. In particular:
- There must be at least 2 (two) authoritative nameservers for the domain name and they must exactly match those in the registration request for the domain name or for change of hosts;
- a CNAME record cannot be associated with the domain name;
- the name of the nameserver specified in the SOA record cannot be a CNAME;
- the names of the authoritative nameservers for the domain name cannot be CNAME records;
- the IPv4 and (if specified) the IPv6 addresses of the hosts for the domain name must match those actually associated with them in the DNS;
- the IPv4 and (if specified ) the IPv6 addresses of the hosts for the domain name must both give authoritative responses;
- a CNAME cannot be associated with the MX record, if present;
- if, during the verification procedure, at least one nameserver returns one of the following responses:
- Not responding
- Not reachable
- Not running
- Non-existent domain
- Host not found
- Server failure
- Query failed
- all hosts present in the registration must be authoritative for the domain name registered.
Once NS (Name Server) have been configured, you can follow our guideline to change NS on domain name.
Common mistakes during Name Server change
Below you can find the list of the checks carried out for each host subject to DNS validation is as follows:
- Name ServersResolvableTest: check which nameservers it was possible to resolve
- Name ServersAnswerTest: check for which nameservers the query gave a response
- IPSOATest: if a nameserver has more than one IP address, make an SOA query to each address checking that they respond authoritatively and that the serial numbers match
- Name ServerReturnCodeTest: check that the header of the response to the queries made to the nameservers to be validated contains the return-code NOERROR
- AATest: check whether the nameservers to be validated are authoritative for the domain name registered
- NSCountTest: check that the number of NS records is between 2 and 6
- NSCompareTest: check the correspondence between the nameservers listed in the request for registration or modification of the hosts and those present in the NS records of the zone file
- CNAMEHostTest: check that the nameservers present in the SOA records, NS and MX, if present, are not CNAME records.
To make the redirect access a fixed IP, we recommend using a DNS Manager like Linode.How to create a DNS zone on Linode panel:
- From DNS Manager panel, click on "add a domain zone";
- add your data for every record.
- Ensure that the new NS (Name Server) are correctly resolving. More info about this on point 8
The Italian NIC has an internal verification test for which it first of all puts the domain in "pendingUpdate" and at the same time checks whether
the new configuration is functioning. If over the next three days it is not verified, it is rejected and the domain returns to "ok" status.
In the opposite case, i.e. if the configuration is working, it starts the propagation over all the DNS servers. This operation usually completes in 24 to 72 hours.
Do not worry, it simply means that the DNS have not yet propagated themselves (it is not an instantaneous operation).