If person A sends email to person B and then person B forwards that email to person C.
How can person C find out IP address of a person A.
If that is not possible,then can i find out someones IP addresse if i have only his Email addresse.
For example if i have 123456@yahoo.com,can i find out the IP addresse of that email.
It is not possible that person C find out IP address from forwarded email from person A.
Ask person B to forward you email header from email received by person A. Then investigate who is person A with email trackers:
http://www.ipaddresslocation.org/email-tracking/email-header.php
http://www.ip-address.org/tracker/trace-email.php
http://www.find-ip-address.org/email-search/find-email.php
Good luck!