Lesson 5

Dates: 6/12/2017
Linux networking
Linux System Administration


TCP and UDP ports
  • Protocols TCP and UDP act as port managers for user applications.
  • Some ports listed in /etc/services:
      systat 11/tcp users daytime 13/tcp daytime 13/udp netstat 15/tcp qotd 17/tcp quote msp 18/tcp # message send protocol msp 18/udp chargen 19/tcp ttytst source chargen 19/udp ttytst source ftp-data 20/tcp ftp 21/tcp fsp 21/udp fspd ssh 22/tcp # SSH Remote Login Protocol ssh 22/udp telnet 23/tcp smtp 25/tcp mail
  • Ports under 1024 are privileged ports.
  • Socket = Port + IP address.
    Any new connection opens a new socket.



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