Core Solutions of Microsoft SharePoint Server 2013

Note:
Example:
This message made it sound like the service application wasnt created or that it wasnt in this web applications proxy group. Use the Managed Metadata Service
Application to fix this problem.

To enable anonymous access to a web application, do the following:
From Central Administration, select Application Management.
On the Application Management page, click the URL area of your desired webapplication. From the ribbon, in the Security section, select the Authentication

Providers icon on the ribbon -

Choose the appropriate zone for which you want to enable anonymous access

On the Edit Authentication page, scroll to the section that reads Anonymous Access. Select the Enable Anonymous Access check box shown in Figure 2-10.

Note:
* Reverse proxy server A reverse proxy server that supports Secure Sockets Layer (SSL), such as Microsoft Forefront Unified Access Gateway (UAG), enables you to publish SharePoint sites across the corporate firewall.
* See step 2 below:
After the SharePoint site is published outside the firewall, you must add the site to a zone that allows for cross-firewall access. A cross-firewall access zone is used to generate external PC and mobile URLs in mobile alert messages, and enables users to send an externally available URL when they click the E-mail a link or Alert Me button on the ribbon.
To configure a cross-firewall access zone
✑ Verify that you have the following administrative credentials:
✑ You must be a member of the Farm Administrators group.
✑ 2. In Central Administration, click System Settings.
✑ 3. On the System Settings page, under Farm Management, click Configure cross firewall access zone.
✑ 4. On the Cross Firewall Access Zone page, in Web Application, in the Web Application list, select the web application that is published across the firewall.
✑ 5. In Cross Firewall Access Zone, in the Zone selection for cross firewall access list, select the zone that is published across the firewall.
Reference: Configure external access for mobile devices in SharePoint 2013

Note:
* Make the account in the SharePoint domain.
* Step 1: Create accounts that are required for a SharePoint Search service application

To register a managed account -
✑ On the Central Administration home page, in the Quick Launch, click Security.
On the Security page, in the General Security section, click Configure managed accounts.

✑ On the Managed Accounts page, click Register Managed Account.
✑ On the Register Managed Account page, in the Account Registration section, type the user name and password that you want to use as credentials for the service account.
✑ If you want SharePoint Server 2013 to manage password changes for this account, select the Enable automatic password change check box and configure the parameters for automatic password change.
✑ Click OK.
Step 2: Configure the SharePoint Search service
Reference:https://technet.microsoft.com/en-us/library/gg502597.aspx