Tutorial 6

DNS Functions

Commands demonstrated

<?gethostbyname()>
<?gethostbyaddr()>

These functions are used to translate IP addresses into domain names and vice versa. To convert from an IP address to a domain name use gethostbyaddr("IP"). And to convert from a domain name to an IP address use gethostbyname("domain.name").

Example.

Convert the IP address 18.159.0.42 into its domain name. To do this we execute the following command:

<?echo gethostbyadrr("18.159.0.42")>

The result is: AENEAS.MIT.EDU

And to convert from an address like www.yahoo.com to its IP address we execute this command:

<?echo gethostbyname("www.yahoo.com")>

The result is: 205.216.146.69