Linux Server Security Settings disable useless ports

Article Title: Linux Server Security Settings disable useless ports. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

Currently, many small and medium users are constantly updating or upgrading their networks due to business development, which leads to great differences in their user environments. The entire network system platform is uneven, and most servers use Linux systems, the PC end uses the Windows system. Therefore, in enterprise applications, Linux/Unix and Windows operating systems coexist to form a heterogeneous network. Small and medium-sized enterprises often lack comprehensive considerations for network security due to lack of experienced Linux network administrators and security product procurement funds. I will solve the troubles of enterprises from the aspects of server security and network device security.

Disable useless ports

Any network connection is implemented through open application ports. If we open the port as few as possible, we will turn the network attack into the source water, which greatly reduces the chance of successful attackers.

First check your inetd. conf file. Inetd monitors certain ports to provide necessary services. If someone develops a special inetd daemon, there is a security risk. You should comment out the services that will never be used in the inetd. conf file (such as echo, gopher, rsh, rlogin, rexec, ntalk, and finger ). Note: Unless absolutely required, you must comment out rsh, rlogin, and rexec. telnet recommends that you use a more secure ssh instead and then kill the lnetd process. In this way, inetd no longer monitors the daemon on your machine, so that no one can use it to steal your application port. You 'd better download a port scanner to scan your system. If you find an open port that you don't know, immediately find the process using it to determine whether to close it.