SharePoint in Extranet
Microsoft Internet Security and Acceleration Server 2000 SharePoint Portal Server Deployment Kit - https://www.isaserver.org/img/upl/spskit/3quickstart/3quickstart.htm
Reverse Proxy Configurations for Windows SharePoint Services - https://www.microsoft.com/technet/prodtechnol/windowsserver2003/technologies/sharepoint/revproxy.mspx