The previous article on SharePoint's outgoing e-mail, this article explains how incoming mail should be configured. This article is written according to the structure of the content on TechNet.
SharePoint 2013 uses Exchange 2013 to configure outgoing messages
First you need to install the SMTP relay server on the SharePoint server.
1. Install SMTP Service
Verify that the user account that is executing this procedure is a member of the Administrators group on the front-end Web server.
Click Start, point to Administrative Tools, and then click Server Manager. There is no Start menu in Server 2012, so just click on the Windows key and find "admin tools" in the Start screen. Or click on the Server Manager directly in the taskbar.
In Server Manager, click Add Roles and Features.
In the Start screen, click Next.
(Here do not know whether 2012 have become so, or I installed the datacenter?) Select your SharePoint Server.