Question:Define DNS. 

The Domain Name System (DNS) allows to use domain names (e.g. yahoo.com) in place of the corresponding IP address, such as 192.0.32.166.

Question:What is domain name server? 

The domain names and their complementary IP addresses are stroed on domain name servers, which are interspersed across the globe.

Question:What are the five  configuration directives that pertinent to PHP mail() function? 

1. SMTP=string, Scope:PHP_INI_ALL
2. sendmail_from=stirng, Scope:PHP_INI_ALL
3. sendmail_path=string, Scope:PHP_INI_SYSTEM
4. smtp_port=integer, Scope:PHP_INI_ALL
5. mail.force_extra_parameters=string, Scope:PHP_INI_SYSTEM

Question:Explain the parameters of PHP’s mail function. 

The PHP mail() function is used to send emails from inside a script.

Prototype:

boolean mail(string to, string subject, string message [, string addl_headers [, string addl_params]])

Parameter
Description
to
Required. Specifies the receiver / receivers of the email
subject
Required. Specifies the subject of the email. Note: This parameter cannot contain any newline characters
message
Required. Defines the message to be sent. Each line should be separated with a LF (\n). Lines should not exceed 70 characters
headers
Optional. Specifies additional headers, like From, Cc, and Bcc. The additional headers should be separated with a CRLF (\r\n)
parameters
Optional. Specifies an additional parameter to the sendmail program


Example:

<?php
   
    mail("client@example.com","This is a subject","This is the mail body","from:admin@example.com\r\n");

?>

Question:Name five internet services that commonly operates on a particular communications port. 

1. HTTP - Hyper Text Transfer Protocol
2. FTP - File Transfer Protocol
3. POP3 - Post Office Protocol
4. IMAP - Internet Message Access Protocol
5. SSH - Secure SHell

Question:How do you retrive internet service port number in php? 

The getservbyname() function returns the port number of a specified service.

Prototype:

int getservbyname(string service, string protocol)

Example:

<?php
   echo "HTTP's default port number is: ".getservbyname("http","tcp");

?>

Question:How do you get a socket connection in php? 

The fsocketopen() function establishes a connection to the resource designated by target on port.

Prototype:

resource fsockopen( string target, int port [, int erron [, string errsting [, float timeout]]])

Example:

<?php
   $http=fsockopen("www.example.com",80);
  
   $req="GET / HTTP/1.1\r\n";
   $req.="Host: www.example.com\r\n";
   $req.="Connection: Close\r\n\r\n";

  fputs($http,$req);
 
  while(!feof($http)){

      echo fgets($http,1024);

   }
fclose($http);
 
?>

Question:What do you mean by directory service? 

Directory Service: It offers system administrators, developers, and end users alike a consistent, efficient, and secure means for viewing and managing resources such as people, fles, printers, and applications.

Question:How do you connect to an LDAP server? 

The ldap_connect() function establishes a connection to an LDAP server identified by a specific host name and optionally a port number.

Prototype:

resource ldap_connect([stiring hostname[, int port]])

Example:

<?php
   $host="ldap.wjgilmore.com";
   $post="389";
   $connection=ldap_connect($host,$port) ro die("Can't establish LDAP connection");
?>

Question:What do you mean by web service? 

Web service: Web services are typically application programming interfaces (APIs) or web APIs that are accessed via Hypertext Transfer Protocol (HTTP) and executed on a remote system hosting the requested services.