The Domain Name System (DNS) is a hierarchial naming system for computers, services, or resources connected to the internet. It allows translation of IP addresses into names in order to search for, and locate web sites and other networking equipment. It is akin to the functionality of a phone book, i.e. tying names to numbers.
DNS grants the responsibility of assigning domain names and associate those names to IP address to the authoritative name servers for each domain. Typically this name server is where the domain name was purchased or is currently hosted (they can be transferred). The name server then in turn can assign other authoritative name servers for sub domains. For example a domain hosted with ITSN has a name server that relays information for individual domains, and that domain can then specify its own name server. In web hosting it is best practice to specify the same name server for a domain as the one where the web site resides.
The name server for a domain provides what is know as Resource Records (RR). Each record listed has a type, an expiration limit (TTL), a class, and type specific information. For hosting purposes the following record types are most commonly used:
Common Resource Records
DNS record information resides with the hosting provider (domain registrar) the domain was registered through. If the domain provider is unknown, it may be determined using a free whois lookup through mxtoolbox.com. Once hosting information is ascertained, access the admin panel for the domain via the provider's web site and locate the page to directly modify DNS settings*.
For web hosting the recommended approach is to modify the Name Server record to point to those belonging to ITSN. Modify the Name Server (NS) records to the two following entries:
By changing the name server records to those hosted by ITSN all requisite records for the web site, and future record entries for any other hosted service will automatically be added and configured in the organization's online service control panel. The DNS configuration at this point is done, and no further modifications are necessary. Save the changes made to the DNS entries, and allow up to 24 hours for the record changes to take. Typically DNS changes made resolve within two to three hours within the United States, however international clients may be presented with the full delay.
If the organization elects not to utilize ITSN's name servers it will be necessary to make three A record entries pointing to the IP Address of the web site. The name value of the records, which designates the prefix of the domains (i.e. www) need to be included in the records as follows:
The three name entries cover a blank, all, and www prefix respectively for internet queries to the hosted website. Save the changes made to the DNS entries, and allow up to 24 hours for the record changes to take. Typically DNS changes made resolve within two to three hours within the United States, however international clients may be presented with the full delay.
*Note: ITSN cannot provide support for the numerous DNS control panels. Consequently any help needed to make a change on an external domain management site must go through that company. Provide their support team with the settings and will be able to help add the records.