services(5) File Formats Manual services(5) (NAME) services - (DESCRIPTION) services (ASCII) . ( ) . C getservent(3) getservbyname(3) getservbyport(3) setservent(3) endservent(3) . IANA ( ) TCP UDP . TCP . ( <<>>) ( root) ( bind(2) tcp(7) udp(7)). . (Well-known ports) IANA . services . inetd.conf(5) . inetd(8) inetd.conf(5) . (NNTP) (SMTP) . services _PATH_SERVICES . /etc/services . : service-name port/protocol [aliases ...] : service-name . (case- sensitive). service-name . port ( ) . protocol . protocols(5) . tcp udp . aliases (space) (tab) . . (space) (tab) . () (#) . . (service-name) . service-name . . a-z 0-9 (-) . . ( getservent(3) getservbyname(3) getservbyport(3) .) NIS/Yellow Pages Hesiod/BIND . services : netstat 15/tcp qotd 17/tcp quote msp 18/tcp # message send protocol msp 18/udp # message send protocol chargen 19/tcp ttytst source chargen 19/udp ttytst source ftp 21/tcp # 22 - unassigned telnet 23/tcp (FILES) /etc/services _PATH_SERVICES (SEE ALSO) listen(2), endservent(3), getservbyname(3), getservbyport(3), getservent(3), setservent(3), inetd.conf(5), protocols(5), inetd(8) RFC (Assigned Numbers RFC) RFC 1700 ( STD0002). Linux man-pages 6.9.1 2024-05-02 services(5)