SPF

   The Sender Policy Framework (SPF) is an email-authentication technique which is used to prevent spammers from sending messages on behalf of your domain. With SPF an organisation can publish authorized mail servers.

Microsoft Office 365

   Microsoft Office 365 is a Software as a Service (SaaS) solution that includes Microsoft Office and other services, such as email and collaboration, from Microsoft’s cloud server. Microsoft Office 365 provides desktop functionalities and is available by subscription.

Nginx

   Nginx is a web server which can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache. The software was created by Igor Sysoev and first publicly released in 2004. A company of the same name was founded in 2011 to provide support and Nginx plus paid software.

Microsoft-IIS 7.5

   Internet Information Services (IIS, formerly Internet Information Server) is an extensible web server created by Microsoft for use with the Windows NT family.

ASP.NET

   ASP.NET is an open-source server-side web application framework designed for web development to produce dynamic web pages.

Plesk

   Plesk is a commercial web hosting platform with a control panel that allows a server administrator to set up new websites, reseller accounts, e-mail accounts

Server partial requests support

   The Accept-Ranges response HTTP header is a marker used by the server to advertise its support of partial requests. The value of this field indicates the unit that can be used to define a range.

Gzip Content-Encoding

   The Content-Encoding entity header is used to compress the media-type. When present, its value indicates which encodings were applied to the entity-body. It lets the client know how to decode in order to obtain the media-type referenced by the Content-Type header.

Vary Header Accept-Encoding

   The Accept-Encoding request HTTP header advertises which content encoding, usually a compression algorithm, the client is able to understand. Using content negotiation, the server selects one of the proposals, uses it and informs the client of its choice with the Content-Encoding response header.