TCP Wrappers

TCP Wrappers is enabled by default RHEL 7 system of a traffic monitoring program that can be made to allow or deny the operation in accordance with the visiting and host address of the machine target service program. In other words, Linux system actually has two levels of firewalls, first mentioned in front of filter traffic TCP / IP protocol-based tools, and TCP Wrappers service is able to enable or disable the Linux firewall system to provide services, thereby protecting the safe operation of Linux systems at a higher level. TCP Wrappers services firewall policy is controlled by two control list file, the user can edit the list of files to allow controlled release of a request for service traffic, you can also edit refuse control list file to block traffic for a service request. After the file control list changes will take effect immediately, allows the control system will first check the list of files (/etc/hosts.allow), if the match to allow the release of strategy phase flow; if there is no match, then the match refused to go further control list file (/etc/hosts.deny), if a match is found then reject the traffic. If these two files are all no match to the default release traffic. TCP Wrappers Control List configuration file services not complicated,