TCP Wrappers is a security tool for Linux and Unix-like systems that allows you to control access to network services based on the hostname or IP address of the client. TCP Wrappers works by intercepting incoming connection requests and checking them against a configuration file (/etc/hosts.allow and /etc/hosts.deny) to determine whether the connection should be allowed or denied.
To find out if a program is compiled with TCP Wrappers support, you can use the ldd command to list the dynamic dependencies of the program. If the program is linked to the libwrap.so library, it is compiled with TCP Wrappers support.
For example:
ldd program
This will show the dynamic dependencies of the program executable. If libwrap.so is listed, the program is compiled with TCP Wrappers support.
Alternatively, you can use the lsof command to list the open files of the program. If the program executable has the /etc/hosts.allow or /etc/hosts.deny files open, it is using TCP Wrappers.
For example:
lsof -p PID
This will show the open files of the process with ID PID. If /etc/hosts.allow or /etc/hosts.deny are listed, the program is using TCP Wrappers.
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