Security Strategies in Linux Platforms and Applications, 3rd Edition

Services on Every TCP/IP Port

Because more than 65,000 port numbers are associated with Transmission Control Protocol/Internet Protocol (TCP/IP) services, accounting for different network services can get confusing. To reduce confusion, the Internet Assigned Numbers Authority (IANA) registers and manages well-known port numbers and protocols. The list of well-known port numbers includes hundreds of services that have been registered to specific port numbers.

The association between port numbers and services is documented in the /etc/services file. Other Linux configuration options refer to this file. For example, when the iptables command is used to configure a firewall on a Red Hat system, the associated rules are stored in the /etc/sysconfig/iptables ...