Link to home
Start Free TrialLog in
Avatar of Troupe75
Troupe75

asked on

Obtaining public and private ip addresses

When I go to: http://www.whatismyip.com/ I get my public ip address 69.132.x.x  (the ip address that is assigned to the public interface on my router.  When I go to: http://whatismyip.org/ I get my DHCP assigned private ip address of 192.168.1.41 (this is the address actually assigned to my computer's ethernet card).

I know how to get my public ip address using server side scripting in JSP, PHP or cgi scripts, but I don't know how to get my private ip address.  Originally I thought the only way to do this was with some type of client side scripting, but http://whatismyip.org/ appears to be retrieving the client side ip address using only server side scripting.

How is this done?  
Avatar of Adam314
Adam314

When I go to either of those, it shows only my public IP address.

It may be that your web client is providing the information in a header.  What web client are you using?  Can you try using FireFox with the LiveHTTPHeaders add-on?  This will tell you if your web client is providing the information.
Avatar of Troupe75

ASKER

I've tried it with Firefox, Safari, and curl so I don't think it is coming from the web browser.  I'm not using the LiveHTTPHeaders add-on in Firefox.
SOLUTION
Avatar of Adam314
Adam314

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Last login: Wed Oct 15 18:51:33 on console
~  $ nslookup whatismyip.org
Server:            192.168.1.6
Address:      192.168.1.6#53

Non-authoritative answer:
Name:      whatismyip.org
Address: 206.176.224.3


I have a DHCP assigned address.  The network goes through a Barracuda content filter and then Nat through a Firebox firewall to a T1.

I'm not sure how the private address is getting passed out.  When I go one of my websites and look at the logs, it show my public ip (the one on the firebox).  I'm not sure if there is a way to run Apache in a mode that will show the full request headers.
ASKER CERTIFIED SOLUTION
Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Yes, that must be it.  I don't think you could use that very reliably, as I don't think most NAT boxes will add it.