libwrap is a free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

 program library that implements generic TCP Wrapper

TCP Wrapper

TCP Wrapper is a host-based networking ACL system, used to filter network access to Internet Protocol servers on operating systems such as Linux or BSD...

 functionality for network service

Network service

Network services are the foundation of a networked computing environment. Generally network services are installed on one or more servers to provide shared resources to client computers.- Network services in LAN :...

 daemon

Daemon (computer software)

In Unix and other multitasking computer operating systems, a daemon is a computer program that runs as a background process, rather than being under the direct control of an interactive user...

s to use (rather than, or in addition to, their own host access control

Access control

Access control refers to exerting control over who can interact with a resource. Often but not always, this involves an authority, who does the controlling. The resource can be a given building, group of buildings, or computer-based information system...

 schemes).

Originally part of the tcp_wrappers package, it per default was compiled as a static archive, and is still used as such in some places, for instance in Slackware Linux 10.2. However most other FOSS

Free and open source software

Free and open-source software or free/libre/open-source software is software that is liberally licensed to grant users the right to use, study, change, and improve its design through the availability of its source code...

 Unix-like

Unix-like

A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....

 distributions, such as Debian

Debian

Debian is a computer operating system composed of software packages released as free and open source software primarily under the GNU General Public License along with other free software licenses. Debian GNU/Linux, which includes the GNU OS tools and Linux kernel, is a popular and influential...

, Red Hat

Red Hat

Red Hat, Inc. is an S&P 500 company in the free and open source software sector, and a major Linux distribution vendor. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina with satellite offices worldwide....

 and NetBSD

NetBSD

NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...

, applied patches to the Makefile in order to compile it to a shared-object and generally include that as part of their base system. Some even decouple it (and testing utilities) from 'tcpd', which is then provided as an additional package

Software package (installation)

In package management systems, which are commonly used with Linux-based operating systems, a package is a specific piece of software which the system can install and uninstall....

.

One of the possible problems for end-user (sysadmins

System administrator

A system administrator, IT systems administrator, systems administrator, or sysadmin is a person employed to maintain and operate a computer system and/or network...

) to this situation is that the soname

Soname

In Unix operating systems, a soname is a field of data in a shared object file. The soname is a string, which is used as a "logical name" describing the functionality of the object...

 is not standardized, although it generally is libwrap.so.0.7.6 in Linux distribution

Linux distribution

A Linux distribution is a member of the family of Unix-like operating systems built on top of the Linux kernel. Such distributions are operating systems including a large collection of software applications such as word processors, spreadsheets, media players, and database applications...

s, and libwrap.so.2, 3 or 7 on BSD Unix systems.

See also

• TCP Wrapper
  TCP Wrapper
  TCP Wrapper is a host-based networking ACL system, used to filter network access to Internet Protocol servers on operating systems such as Linux or BSD...
  
  
• Autoconf
  Autoconf
  GNU Autoconf is a tool for producing configure scripts for building, installing and packaging software on computer systems where a Bourne shell is available....
  
  
• Unix security
  Unix security
  Unix security refers to the means of securing a Unix or Unix-like operating system. A secure environment is achieved not only by the design concepts of these operating systems, but also through vigilant user and administrative practices.- Permissions :...
  
  
• Access control list
  Access control list
  An access control list , with respect to a computer file system, is a list of permissions attached to an object. An ACL specifies which users or system processes are granted access to objects, as well as what operations are allowed on given objects. Each entry in a typical ACL specifies a subject...
  
   (ACL)

External links

• OpenBSDs'
  OpenBSD
  OpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution , a Unix derivative developed at the University of California, Berkeley. It was forked from NetBSD by project leader Theo de Raadt in late 1995...
  
  tcpd.c as libwrap usage example code
• PHP interface: tcpwrap_check
• Python interface: PyTCPWrap
• Ruby interface: libwrap-ruby (originally ruby-tcpwrap)
• Apache module: mod_hosts_access
• PAM module: pam_tcpd