Wrapper

What Does Wrapper Mean?

A wrapper is a program used in Transmission Control Protocol (TCP) to provide a layer of security by intercepting calls to computer services and determining whether the service is authorized to execute. A wrapper provides the necessary protection against host name and host address spoofing. The determination of whether to provide access to requests is done with the help of a system administrator, who adds entries in the TCP wrapper configuration files /etc/hosts.allow and /etc/host.deny after installing the wrapper program. Whenever an incoming request for servers started by inetd arrives, the wrapper checks in the two configuration files and allows or denies access accordingly.

In this context, a wrapper is also known as a TCP wrapper.

Techopedia Explains Wrapper

A wrapper has the following characteristics:

• Monitors and filters all incoming requests for network services, such as EXEC, TFTP, TALK, FTP, FINGER, etc.
• Provides extensive logging services
• Makes sure there are no impacts in system performance or with authorized users
• Passes control to the real associated network program
• Employs a trap-setting feature to take appropriate actions on the host

A TCP wrapper has a few drawbacks:

• It will not function with programs that are not using TCP or Internet Protocol
• Will not work on applications that are frequently running
• Does not provide cryptographic authentication