ArcGIS Web Adaptor (IIS) is a required component of Portal for ArcGIS which allows you to integrate your portal with your existing web server and your organization's security mechanisms. You cannot deploy Portal for ArcGIS in your organization without the Web Adaptor.
The Web Adaptor is an application that runs in your existing website and forwards requests to the machine hosting Portal for ArcGIS. The IIS setup is compatible with IIS versions 7.0, 7.5, 8.0, and 8.5.
Benefits of the Web Adaptor
The Web Adaptor provides the following benefits:
Allows you to integrate Portal for ArcGIS with your organization's existing web server. By including a web server in your site, you gain the ability to host web applications that use your GIS services.
Allows you to use your organization's identity store and security policies at the web-tier level. For example, if you're using IIS, you can use Integrated Windows Authentication to restrict who enters the portal. You can also use Public Key Infrastructure (PKI) or any other identity store for which the web server has built-in or extensible support. This allows you to provide a single sign-on or other custom authentication experience when logging in to use services, web applications, and Portal for ArcGIS.
Allows you to expose Portal for ArcGIS through a site name other than the default arcgis.
Allows you to expose Portal for ArcGIS through port 80 or 443.
Web Adaptor deployment scenarios
The Web Adaptor's version must always match the version of Portal for ArcGIS. If you've configured multiple Web Adaptors on a single web server, you can use different version numbers for all the Web Adaptors.
The Web Adaptor is platform independent of Portal for ArcGIS; therefore, the Web Adaptor you deploy does not have to match the operating system platform of your portal. For example, if your portal is running on Linux, you can deploy ArcGIS Web Adaptor (IIS) to work with Portal for ArcGIS.
Accessing your portal with the Web Adaptor installed
After installing and configuring the Web Adaptor, the URL that you use to access your portal will be in the format https://webadaptor.domain.com/arcgis/home. For example, if the machine hosting your Web Adaptor is named wa with the domain myorg.net and your Web Adaptor is named arcgis, you'll access the portal using the URL https://wa.myorg.net/arcgis/home.
If you have configured your portal to use SSL for all communication, you should update the installed portal website and help shortcut URLs to use https instead of http; otherwise, you will see failures in your browser when attempting to access the original shortcut URLs.
The Web Adaptor setup experience
The Web Adaptor has its own setup and installation guide which is separate from the Portal for ArcGIS installation. You must install the Web Adaptor on a machine running a web server. This can be a machine already running Portal for ArcGIS or a separate machine.
To learn more about the setup experience, see An overview of implementing the Web Adaptor with Portal for ArcGIS.