I have Exchange server in my work place and deploy it and give it real ip and enable through my firewall i open it from any wan by using its real ip i need to deploy to any user open it from any wan without real ip i want any user to open it through http:\\ link like Http:\\imail.microsft.uk can any one help me

I assume you want to publish OWA or you OA. You will need to create an A record in your external DNS server pointing to your Exch server. Then ask users to access this URL. You would want to publish on 443 to secure it.Sukh