Find The IP Address Of Sender In YAHOO...

Finding IP address in Yahoo! Mail
Steps:
1. Log into your Yahoo! mail with your username and password.

2. Click on Inbox or whichever folder you have stored your mail.

3. Open the mail.

4. If you don't see the headers above the mail message, your headers are not displayed.
    To display the headers,
* Click on Options on the top-right corner.
* In the Mail Option page, click on General Preferences.
* Scroll down the Messages where you have the Headers option.
* Make sure that Show all headers on incoming messages is selected.
* Click on Save button.
* Go back to the mails and open that mail.

5. You should see similar headers like this Yahoo! headers: namelook for received: from followed 
    by the IP address between square brackets [ ]. Here, it is 202.65.138.109. That is be the IP
    address of the sender!

6. Track the IP address of the sender.