Identify IP Addresses and Host Names

We can identify the IP addresses of all the client connect to server. Below the command to identified  the IP address ,machine name,sid  .

SQL>   select   sid,   machine,     UTL_INADDR.get_host_address (substr(machine,instr(machine,'\')+1))  ip  from   v$session   where   type='USER'   and    username is not null   order  by   sid;

Oracle provides the method to identifying and relating to the IP addresses and host names  for Oracle clients and servers. The few methods  are  : 

1.) UTL_INADDR
2.) SYS_CONTEXT
3.) V$INSTANCE
4.) V$SESSION

1.) UTL_INADDR  :  The UTL_INADDR package provides a PL/SQL procedures to support internet addressing. It provides an API to retrieve host names and IP addresses of local and remote hosts.The utl_inaddr like the two function  : 

1.) get_host_address and 
2.) get_host_name.

Now we check the description of UTL_INADDR 

SQL> desc UTL_INADDR

FUNCTION  GET_HOST_ADDRESS  RETURNS  VARCHAR2
 Argument Name                Type                In/Out         Default?
 -----------------          ------------           --------      -------------
 HOST                         VARCHAR2            IN           DEFAULT
FUNCTION GET_HOST_NAME RETURNS VARCHAR2
 Argument Name               Type                    In/Out             Default?
 ----------------           ---------------        --------          ------------
 IP                                 VARCHAR2            IN                DEFAULT

I.) Get_host_address: The get_host_address function like the argument name "HOST" , data types "varchar2" and by default NULL. The get_host_address get local IP address and remote host given its IP address.

II.) Get_host_name: The get_host_name function like the argument name "IP" , data types "varchar2" and by default NULL. The get_host_name get local host name and remote host given its name.

Let see some example : 

The GET_HOST_ADDRESS function returns the IP address of the specified host name

SQL>select  UTL_INADDR.get_host_address('TECH-284') from  dual;

UTL_INADDR.GET_HOST_ADDRESS('TECH-284')
-----------------------------------------------------------
192.100.0.85

The GET_HOST_NAME function returns the host name of the specified IP address.

SQL> SELECT UTL_INADDR.get_host_name('192.168.52.127') FROM dual;

UTL_INADDR.GET_HOST_NAME('192.168.52.127')
----------------------------------------------------------
tech-199

The host name of the database server is returned if the specified IP address is NULL or omitted.

2.) SYS_CONTEXT : Oracle has a very useful built-in function called SYS_CONTEXT. The SYS_CONTEXT function is able to return the following host and IP address information for the current session.SYS_CONTENT has the following options as 

TERMINAL - An operating system identifier for the current session. This is often the client machine name.
HOST - The host name of the client machine.
IP_ADDRESS - The IP address of the client machine.
SERVER_HOST - The host name of the server running the database instance.

What makes this function more interesting is the fact that Oracle provides a built-in namespace called USERENV with predefined parameters, which describes the current session.

The syntax of this function goes like this:
SYS_CONTEXT ( 'namespace' , 'parameter' [, length] )

Let see some example :

SQL> SELECT SYS_CONTEXT('USERENV','TERMINAL') FROM dual;
SYS_CONTEXT('USERENV','TERMINAL')
---------------------------------------------------
TECH-199

SQL> SELECT SYS_CONTEXT('USERENV','HOST') FROM dual;
SYS_CONTEXT('USERENV','HOST')
------------------------------------------
TECH\TECH-199

SQL> SELECT SYS_CONTEXT('USERENV','IP_ADDRESS') FROM dual;
SYS_CONTEXT('USERENV','IP_ADDRESS')
--------------------------------------------------
192.100.0.112

SQL> SELECT SYS_CONTEXT('USERENV','SERVER_HOST') FROM dual;
SYS_CONTEXT('USERENV','SERVER_HOST')
-----------------------------------------------------
tech-199

For more about sys_context check the below link .
http://download.oracle.com/docs/cd/B14117_01/server.101/b10759/functions150.htm
http://www.adp-gmbh.ch/ora/sql/sys_context.html

3.) V$INSTANCE :  The host_name column of the V$INSTANCE view contains the host name of the server running the instance.

SQL> SELECT host_name FROM v$instance;
HOST_NAME
-----------------
TECH-199

4.) V$SESSION  :  V$SESSION displays session host information for each current session. The column such as terminal and machine give the following details.
TERMINAL: The operating system terminal name for the client.This is often set to the client machine name.
MACHINE :The operating system name for the client machine.This may include the domain name if present.

SQL> SELECT terminal, machine FROM v$session WHERE username = 'HR';
TERMINAL           MACHINE
-------------       --------------------
TECH-199          TECH\TECH-199


Enjoy    :-)