ServerBuddies Support Blog

what is the root zone?

The DNS translates domain names that humans can remember into the numbers used by computers to look up its destination (a little like a phone book is used to look-up a phone number). It does this in stages. The first place it ‘looks’ is the top level of the directory service - or “root zone”. So to use www.google.com as an example, your computer ‘asks’ the root zone directory (or top level) where to find information on “.com”. After it gets a response it then asks the “.com” directory service identified by the root where to find information on .google.com (the second level), and finally asking the google.com directory service identified by “.com” what the address for www.google.com is (the third level). After that process – which is almost instantaneous – the full address is provided to your computer. Different entities manage each one of these directory services: google.com by Google, “.com” by VeriSign Corporation (other top level domains are managed by other organizations), and the root zone by ICANN.

Naming the IPv4 reverse DNS zone

To properly format the Domain field in the interface using IPv4:

1. Drop the last octet from the IP address.
2. Reverse the order of the remaining octets.
3. Append in-addr.arpa to the end of the remaining octets.
4. Enter this value in the Domain field of the Add a DNS Zone feature.

For example, the reverse DNS zone for 192.168.0.1 is 0.168.192.in-addr.arpa.

You will specify the last octet of the IP address within the zone file.

Domain zone files

Here is an example for a domain file for yourdomain.com. Please note this is a very generic example and there are more features to it. Please refer to the BIND documentation for help with these features.

Any line starting with a ; is a comment line and is ignored by BIND. The first 6 lines are configuration lines for the zone. These lines tell it what the zone is (yourdomain.com) who is responsible for it (root.yourdomain.com which is equivalent to root@yourdomain.com) and a few other things. These other things include a serial number used for keeping track of when it’s updated, how often to refresh the database, how often to retry a zone transfer, when the zone information will expire and a default time to live. *IMPORTANT* Whenever you make changes to the zone file, you MUST increment the serial number. If you do not do this, prolems can occur, especially if you are a primary server supplying information to secondary sites. Most of this information is only used if you have both master and slave systems

The next two lines tell it who the primary DNS server is and who should get the mail for this domain. You can have multiple listings of each of these. To add more dns servers just repeat exactly what is listed changing the dns.yourdomain.com with another dns server. To add another mail server you do the same thing except you have an extra field. The “10″ in the MX line states a priority, lower number being first. What this means is if you have 2 MX listings, one is 10 and one is 20, it will try to deliver the mail to the MX listing with the 10 priority and if it fails it will then go to the MX listing with the 20 priority.

The rest of the zone file lists all your hosts and ips.

You can change the time zone within a php script. Here is a sample code:

With the php tags enter the following

You can set the timezone in .htaccess as well. Add the line:

List of timezones is here: http://us.php.net/manual/en/timezones.php