We have an existing web application and site collection which serves as our main portal.

I need to create an additional web application on the same server, and a site collection on it. This will have entirely different content and will be used only by a specific group of users (board members). These users should not have access to our main portal.

We have:

http://portal (portal.ourdomain.com on port 80)

We'd like, in addition to that:

http://board (board.ourdomain.com)

We already have the new DNS entry pointing to the SharePoint server.

  • Should I create the board application on port 81?
  • Should I provide a Host Header string?
    • If so, would that be 'board.ourdomain.com' or 'http://boardportal'?
  • Do I need to mess with alternate access mappings?

2 Answers 2


You can create a new web application on port 81.

So http://board:81 is your second web application.

  1. board.ourdomain.com
  2. board

Both the above should be A Name Record in the DNS Server pointing to the SharePoint Server (IP Address of the Cluster / the server in the farm hosting Web Front End Services)

Alternate access mapping should be like this for http://board:81 (web application) :

Internet : board.ourdomain.com
Default : http://board
Intranet : http://board

If you just wish to expose http://board over the internet and not http://portal , then you can also create a firewall rule blocking port 80 and allowing port 81 from the internet to the internal lan where your sharepoint is hosted.

  • So I don't need to provide a string in the Host Header field? And the Public URL should be the default "SERVERNAME:81"? Commented Mar 14, 2012 at 13:40
  • Is this answer after 6 years still valid? Is there no need of setting host headers?
    – Emaborsa
    Commented Nov 27, 2018 at 8:22

Since this is a separate web application, you can still use port 80 and specify http://board in your host header. This will work as long as your existing http://portal site is also using only the host header and not the wildcard * where it intercepts all requests to port 80.

As Moss Farmer mentions, you will need to define your Alternate Access Mappings so that the new web application will respond to both http://board and http://board.ourdomain.com

There should not be a need to have anything listening on port 81

  • How can I check whether portal is using the host header or the wildcard? I believe it is the latter. Commented Mar 14, 2012 at 14:06
  • Open IIS Manager, browse to your Portal site and then click on Bindings. That will tell you exactly what it is listening for.
    – Dave Wise
    Commented Mar 14, 2012 at 14:14
  • It appears to be listening on 80 for everything. So, I'll need to leave the Host Header field blank, leave the Public URL at the default value (servername:port) and use Alternate Access Mappings to get board and board.ourdomain. Thanks for your input. Commented Mar 14, 2012 at 14:48
  • No, merely restrict the portal site to the host names it should be listenting for, like portal and portal.ourdomain.com and whatever other URLs are in use. Once restricted, you should be free to set up your board site as detailed.
    – Dave Wise
    Commented Mar 14, 2012 at 15:08

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