TCP Wrapper

TCP Wrapper is an English term which means packing TCP literally. It is about a technique of safety particular to the networks managed by systems Unix.

In order to restrict and to trace the accesses of certain services by providing the origin of the request without to change the sources of the demons nor to reduce the access to services which would allow the attempts at hacking, a program is given the responsability to launch the desired waiter if the customer is authorized to connect itself.

Principle

Instead of launching the desired waiter directly, the program Tcpd is launched to be given the responsability to launch the wanted waiter, if the customer is authorized to connect itself. Thus to derive the requests from connections telnet, the file of configuration /etc/inetd.conf contains this information:

telnet stream TCP nowait root /usr/sbin/in.telnetd in.telnetd

The account root is used by the program Inetd to launch the service (or Demon) in.telnetd to charge with managing connection itself.

See too

Tcpd

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