声明：只是一些摘录而已~
切入正题，咱想看的是服务。附上/etc/inetd.conf 全文先~
# $FreeBSD: src/etc/inetd.conf,v 1.73.10.2.2.1 2009/10/25 01:10:29 kensmith Exp $
#
# Internet server configuration database
#
# Define *both* IPv4 and IPv6 entries for dual-stack support.
# To disable a service, comment it out by prefixing the line with '#'.
# To enable a service, remove the '#' at the beginning of the line.
#
#下行编者加，为了更好理解。就对着看呗
#service-name socket-type protocol {wait|nowait}[/max-child[/max-connections-per-ip-per-minute[/max-child-per-ip]]] user[:group][/login-class]
# server-program server-program-arguments
#ftp stream tcp nowait root /usr/libexec/ftpd ftpd -l
#ftp stream tcp6 nowait root /usr/libexec/ftpd ftpd -l
#ssh stream tcp nowait root /usr/sbin/sshd sshd -i -4
#ssh stream tcp6 nowait root /usr/sbin/sshd sshd -i -6
#telnet stream tcp nowait root /usr/libexec/telnetd telnetd
#telnet stream tcp6 nowait root /usr/libexec/telnetd telnetd
#shell stream tcp nowait root /usr/libexec/rshd rshd
#shell stream tcp6 nowait root /usr/libexec/rshd rshd
#login stream tcp nowait root /usr/libexec/rlogind rlogind
#login stream tcp6 nowait root /usr/libexec/rlogind rlogind
#finger stream tcp nowait/3/10 nobody /usr/libexec/fingerd fingerd -s
#finger stream tcp6 nowait/3/10 nobody /usr/libexec/fingerd fingerd -s
#
# run comsat as root to be able to print partial mailbox contents w/ biff,
# or use the safer tty:tty to just print that new mail has been received.
#comsat dgram udp wait tty:tty /usr/libexec/comsat comsat
#
# ntalk is required for the 'talk' utility to work correctly
#ntalk dgram udp wait tty:tty /usr/libexec/ntalkd ntalkd
#tftp dgram udp wait root /usr/libexec/tftpd tftpd -l -s /tftpboot
#tftp dgram udp6 wait root /usr/libexec/tftpd tftpd -l -s /tftpboot
#bootps dgram udp wait root /usr/libexec/bootpd bootpd
#
# "Small servers" -- used to be standard on, but we're more conservative
# about things due to Internet security concerns. Only turn on what you
# need.
#
#daytime stream tcp nowait root internal
#daytime stream tcp6 nowait root internal
#daytime dgram udp wait root internal
#daytime dgram udp6 wait root internal
#time stream tcp nowait root internal
#time stream tcp6 nowait root internal
#time dgram udp wait root internal
#time dgram udp6 wait root internal
#echo stream tcp nowait root internal
#echo stream tcp6 nowait root internal
#echo dgram udp wait root internal
#echo dgram udp6 wait root internal
#discard stream tcp nowait root internal
#discard stream tcp6 nowait root internal
#discard dgram udp wait root internal
#discard dgram udp6 wait root internal
#chargen stream tcp nowait root internal
#chargen stream tcp6 nowait root internal
#chargen dgram udp wait root internal
#chargen dgram udp6 wait root internal
#
# CVS servers - for master CVS repositories only! You must set the
# --allow-root path correctly or you open a trivial to exploit but
# deadly security hole.
#
#cvspserver stream tcp nowait root /usr/bin/cvs cvs --allow-root=/your/cvsroot/here pserver
#cvspserver stream tcp nowait root /usr/bin/cvs cvs --allow-root=/your/cvsroot/here kserver
#
# RPC based services (you MUST have rpcbind running to use these)
#
#rstatd/1-3 dgram rpc/udp wait root /usr/libexec/rpc.rstatd rpc.rstatd
#rusersd/1-2 dgram rpc/udp wait root /usr/libexec/rpc.rusersd rpc.rusersd
#walld/1 dgram rpc/udp wait root /usr/libexec/rpc.rwalld rpc.rwalld
#pcnfsd/1-2 dgram rpc/udp wait root /usr/local/libexec/rpc.pcnfsd rpc.pcnfsd
#rquotad/1 dgram rpc/udp wait root /usr/libexec/rpc.rquotad rpc.rquotad
#sprayd/1 dgram rpc/udp wait root /usr/libexec/rpc.sprayd rpc.sprayd
#
# example entry for the optional pop3 server
#
#pop3 stream tcp nowait root /usr/local/libexec/popper popper
#
# example entry for the optional imap4 server
#
#imap4 stream tcp nowait root /usr/local/libexec/imapd imapd
#
# example entry for the optional nntp server
#
#nntp stream tcp nowait news /usr/local/libexec/nntpd nntpd
#
# example entry for the optional uucpd server
#
#uucpd stream tcp nowait root /usr/local/libexec/uucpd uucpd
#
# Return error for all "ident" requests
#
#auth stream tcp nowait root internal
#auth stream tcp6 nowait root internal
#
# Provide internally a real "ident" service which provides ~/.fakeid support,
# provides ~/.noident support, reports UNKNOWN as the operating system type
# and times out after 30 seconds.
#
#auth stream tcp nowait root internal auth -r -f -n -o UNKNOWN -t 30
#auth stream tcp6 nowait root internal auth -r -f -n -o UNKNOWN -t 30
#
# Example entry for an external ident server
#
#auth stream tcp wait root /usr/local/sbin/identd identd -w -t120
#
# Example entry for the optional qmail MTA
# NOTE: This is no longer the correct way to handle incoming SMTP
# connections for qmail. Use tcpserver (http://cr.yp.to/ucspi-tcp.html)
# instead.
#
#smtp stream tcp nowait qmaild /var/qmail/bin/tcp-env tcp-env /var/qmail/bin/qmail-smtpd
#
# Enable the following two entries to enable samba startup from inetd
# (from the Samba documentation). Enable the third entry to enable the swat
# samba configuration tool.
#
#netbios-ssn stream tcp nowait root /usr/local/sbin/smbd smbd
#netbios-ns dgram udp wait root /usr/local/sbin/nmbd nmbd
#swat stream tcp nowait/400 root /usr/local/sbin/swat swat
由此，我们看到了很多服务，下面我们来一一的简单学习这些个服务。
