Not getting current IP address in my oracle database
SYS_CONTEXT('USERENV','IP_ADDRESS') returns the ip-address of the client currently connected to the server. 
In your case your toad is connected to Oracle server using loopback ip address(localhost). 
I dont have toad demostrate it but I have tested it in my linux machine.

[oracle@testsrv Desktop]$ sqlplus sys/oracle@192.168.1.50/orcl as sysdba

SQL&gt; select sys_context('USERENV','IP_ADDRESS') from dual;

SYS_CONTEXT('USERENV','IP_ADDRESS')
--------------------------------------------------------------------------------
192.168.1.50

SQL&gt; exit

[oracle@testsrv Desktop]$ sqlplus sys/oracle@localhost/orcl as sysdba

SQL&gt; select sys_context('USERENV','IP_ADDRESS') from dual;

SYS_CONTEXT('USERENV','IP_ADDRESS')
--------------------------------------------------------------------------------
127.0.0.1

SQL&gt;