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Glossary Index

Advanced DNS Options

All FastVirtual hosting plans include advanced DNS options, easily configured from the "Manage DNS" area of the account control panel:

  • A (Host) - An A record is used to to point a host name (i.e. or at an IP address. This is the standard record for translating host names into IP addresses.
  • PTR - A PTR record (often called "Reverse DNS") does the exact opposite of an A record, and points an IP address at a host name. If you wish to add a PTR record for an IP address that is not hosted by FastVirtual, you first need to contact the ISP that issued that IP address, and have them point reverse DNS requests at our name servers ( and If you configure a PTR record before this is done, the record will not work.
  • AAAA (IPv6 Hosts) - AAAA records will be used to point host names to the next generation IPv6 addresses. These addresses are not yet operational, but they are already provided for through our DNS system.
  • MX (Mail Exchange) - An MX record is used to create a mail route for a host name. It must point to an existing host, not an IP address. If you need to point an MX record at an IP address, you must first create an A record (i.e. to point to that IP address. The MX record can then point to this host name. You can add multiple MX records to a domain. If your MX records include priority orders (the lower the number, the higher the priority), the lower priority mail servers will only be used in the event that the higher priority server is inaccessible.
  • CNAME (Alias) - A CNAME record is used to point a subdomain (i.e. at another host name ( or CNAME records must point to other host names. They cannot point to their own host name, an IP address, or a URL.
  • NS (Name Server) - NS records are used to specify authoritative name servers for a host name. NS records are not normally required.
  • SOA (Start of Authority) - An SOA record is used to define specific DNS parameters, including "cache", "default TTL", "expire", "refresh" and "retry".

Most DNS records enable you to enter a TTL (time to live) value, which is used to specify the duration (in seconds) that DNS servers should cache data retrieved from our name servers. TTL is set to 43,200 seconds (12 hours) by default. If you regularly edit DNS information, you may wish to change this to a shorter duration. You should note, however, that some DNS servers may ignore TTL values, in favor of their own default settings.

Note: Only edit records that you are familiar with. Incorrect DNS information can adversely affect your domain name.

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