Central Internet services enables government bureaux and departments as well as government Internet infrastructure services to gain access to the Internet for information dissemination, communication and business transaction with the public.

These services including Web Content Hosting (WCH) service, Internet Access Service (IAS) and Internet Mail Exchange (IMX) service, provide hosting service for government websites, access to the Internet and e-mail communication to government officers. These services were enhanced in 2009 to support the Internet Protocol version 6 (IPv6) to assure a seamless communication with all Internet users using latest networking technology.

In 2013, the IMX was further enhanced by enabling Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM). To strengthen the confidentiality of mail transmission over the Internet, Simple Mail Transfer Protocol over Transport Layer Security (SMTP over TLS) was also enabled on the system using Hongkong Post e-Cert (Server) for transmission encryption. By 2014-15, bureaux and departments with their own Internet mail exchange also enabled SMTP over TLS for better confidentiality of e-mail transmission over the Internet. General adoption of SPF by bureaux and departments was completed by early 2017.