For client/server communications security and identity verification Glink implemented first the Windows standard, SSL (Secure Socket Layer), used by browsers and web servers world wide. SSL security and administration is often already in place because of the need to protect browser <=> web server communication when the clients need to deliver sensitive information, such as credit card numbers, to the server-side applications. SSL can be used for any protocol based on TCP/IP sockets, and thus for Telnet connections between Glink and mainframes (front-ends) with SSL servers. R6.1 of Host Links introduced SSL support on all G&R gateways and servers.
Many UNIX/Linux based sites have instead used SSH (Secure Shell) to ensure client/server communications security and identity verification, primarily for Telnet links.
In R7.2 Glink implements integration with the freeware SSH software PuTTY to allow communication with SSH servers.