While developing often my developers need to know which IP address is of local network when looked from outside. I am working in large outsourcing company and we have local intranet setup. When connecting to remote servers from local system or from remote servers to local system we always want to know our Live IP address.
Previously we have used many different methods to know our Live IP but nothing is reliable. External services often go down or provide incorrect information. I have added new feature to my site where any user can visit the page and find out their outgoing IP address.
Reference : Pinal Dave (http://blog.SQLAuthority.com), IP Address