Quick note for those of you that may be setting up Small Business Server 2011 Essentials servers and are using the online documentation, there is a slight error. Currently the documentation for router configuration links to the wiki article for Small Business Server Standard and the ports required for proper operation of SBS Standard.
The only ports that need to be forwarded for Small Business Server 2011 Essentials are ports 80 and 443. Although, to be honest, you don’t even need port 80. Just train users to use https:// instead of http:// to access the Remote Access website.
P.S. If you use Windows Home Server 2011 or Windows Storage Server 2008 R2 Essentials, the same port(s) need to be forwarded as well.