- 0-1023 -众所周知的端口，也被称为系统端口。
- 1024-49151 -已注册的端口，也被称为用户端口。
- 49152-65535 -动态端口，也被称为专用端口。
/etc/services在Linux中使用文件
cat命令 ：
$ cat /etc/services OR $ cat /etc/services | less
网络服务和端口
# /etc/services: # $Id: services,v 1.48 2009/11/11 14:32:31 ovasik Exp $ # # Network services, Internet style # IANA services version: last updated 2009-11-10 # # Note that it is presently the policy of IANA to assign a single well-known # port number for both TCP and UDP; hence, most entries here have two entries # even if the protocol doesn't support UDP operations. # Updated from RFC 1700, ``Assigned Numbers'' (October 1994). Not all ports # are included, only the more common ones. # # The latest IANA port assignments can be gotten from # http://www.iana.org/assignments/port-numbers # The Well Known Ports are those from 0 through 1023. # The Registered Ports are those from 1024 through 49151 # The Dynamic and/or Private Ports are those from 49152 through 65535 # # Each line describes one service, and is of the form: # # service-name port/protocol [aliases ...] [# comment] tcpmux 1/tcp # TCP port service multiplexer tcpmux 1/udp # TCP port service multiplexer rje 5/tcp # Remote Job Entry rje 5/udp # Remote Job Entry echo 7/tcp echo 7/udp discard 9/tcp sink null discard 9/udp sink null systat 11/tcp users systat 11/udp users daytime 13/tcp daytime 13/udp qotd 17/tcp quote qotd 17/udp quote msp 18/tcp # message send protocol msp 18/udp # message send protocol chargen 19/tcp ttytst source chargen 19/udp ttytst source ftp-data 20/tcp ftp-data 20/udp # 21 is registered to ftp, but also used by fsp ftp 21/tcp ftp 21/udp fsp fspd ssh 22/tcp # The Secure Shell (SSH) Protocol ssh 22/udp # The Secure Shell (SSH) Protocol telnet 23/tcp telnet 23/udp要列出所有开放端口或正在运行的端口，包括在Linux中 的 TCP和 UDP，我们将使用 netstat的 ，是监控网络连接和统计数据的有力工具。
使用Netstat命令列出所有网络端口
$ netstat -lntu Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN tcp 0 0 :::22 :::* LISTEN tcp 0 0 :::80 :::* LISTEN tcp 0 0 :::25 :::* LISTEN udp 0 0 0.0.0.0:68 0.0.0.0:*哪里，
-l-仅打印监听套接字-n-显示端口号-t-启用TCP端口上市-u-允许UDP端口上市
使用ss命令列出所有网络端口
$ ss -lntu Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port udp UNCONN 0 0 *:68 *:* tcp LISTEN 0 128 :::22 :::* tcp LISTEN 0 128 *:22 *:* tcp LISTEN 0 50 *:3306 *:* tcp LISTEN 0 128 :::80 ::* tcp LISTEN 0 100 :::25 :::* tcp LISTEN 0 100 *:25让它成为一个点，通过阅读上面的命令的手册页更多的使用信息。 总之，理解计算机网络中端口的概念对于系统和网络管理员是非常重要的。你可以同时通过这个 netstat的指南简单，准确，很好地解释例子。 最后但同样重要的是，与我们联系，通过共享其他方法在Linux中列出开放端口或通过以下响应表单提出问题。
