とらりもん - Internet skills in 30 min Diff
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!What is IP address and MAC address?
* IP address is an address of the computer in the internet. MAC address is an "ID number" of the "network interface card (NIC)" of the computer.
* Your computer's MAC address does not change forever (unless you replace its NIC).
* Your computer's IP address can change if you change it's connection to the internet.
* It is like your name never changes but your residence address changes when you move from one city to another city.
!!Exercise
* Find IP address and MAC address of the computer in front of you.
* Find IP address and MAC address of your smartphone.
https://www.cman.jp/network/support/go_access.cgi
!"Global IP address" and "private IP address"
* "Global IP address" can be accessed from all over the world DIRECTLY!
* "Private IP address" can be accessed from inside a small network.
!!Exercise
* Is the IP address of the computer in front of you global or private?
* Is the IP address of your smartphone global or private?
!!Discuss with your friend
* What are the advantages and disadvantages of global and private IP address?
!Hostname and DNS
* Hostname is like a nickname for an IP address.
* You can access a single same website using both "hostname" and IP address:
** [[http://pen.envr.tsukuba.ac.jp]]
** [[http://130.158.200.25]]
!!Exercise
* Find the IP address of www.tsukuba.ac.jp
* Find a hostname of 130.158.200.27
!What is a "server" and a "client"?
"Client" is a computer in front of you now. "Server" is a computer working for you through a network. Mostly it is at somewhere else.
!!Example:
* You are watching this website on your client. But it's contents are provided by a server, which is our lab's computer named "pen" (or more officially, "pen.envr.tsukuba.ac.jp"). It is placed in a building near the university library.
!Remote access by SSH
* You can manipulate a server computer freely, using "SSH".
!!Exercise
* Get user account from Nasahara and try SSH access to 130.158.200.25
$ ssh username@130.158.200.25
* Try SSH access to pen.envr.tsukuba.ac.jp
$ ssh username@pen.envr.tsukuba.ac.jp
* Try to see who is using the server:
$ w
!What is "protocol"?
"Protocol" is a rule (procedure) of communication between computers.
!!Example:
* You are watching this website. It's contents are transferred to your client from the "pen" server to your client using a protocol called "HTTP" (hypertext transfer protocol).
!What is "port"?
* IP address is an address of the computer in the internet. MAC address is an "ID number" of the "network interface card (NIC)" of the computer.
* Your computer's MAC address does not change forever (unless you replace its NIC).
* Your computer's IP address can change if you change it's connection to the internet.
* It is like your name never changes but your residence address changes when you move from one city to another city.
!!Exercise
* Find IP address and MAC address of the computer in front of you.
* Find IP address and MAC address of your smartphone.
https://www.cman.jp/network/support/go_access.cgi
!"Global IP address" and "private IP address"
* "Global IP address" can be accessed from all over the world DIRECTLY!
* "Private IP address" can be accessed from inside a small network.
!!Exercise
* Is the IP address of the computer in front of you global or private?
* Is the IP address of your smartphone global or private?
!!Discuss with your friend
* What are the advantages and disadvantages of global and private IP address?
!Hostname and DNS
* Hostname is like a nickname for an IP address.
* You can access a single same website using both "hostname" and IP address:
** [[http://pen.envr.tsukuba.ac.jp]]
** [[http://130.158.200.25]]
!!Exercise
* Find the IP address of www.tsukuba.ac.jp
* Find a hostname of 130.158.200.27
!What is a "server" and a "client"?
"Client" is a computer in front of you now. "Server" is a computer working for you through a network. Mostly it is at somewhere else.
!!Example:
* You are watching this website on your client. But it's contents are provided by a server, which is our lab's computer named "pen" (or more officially, "pen.envr.tsukuba.ac.jp"). It is placed in a building near the university library.
!Remote access by SSH
* You can manipulate a server computer freely, using "SSH".
!!Exercise
* Get user account from Nasahara and try SSH access to 130.158.200.25
$ ssh username@130.158.200.25
* Try SSH access to pen.envr.tsukuba.ac.jp
$ ssh username@pen.envr.tsukuba.ac.jp
* Try to see who is using the server:
$ w
!What is "protocol"?
"Protocol" is a rule (procedure) of communication between computers.
!!Example:
* You are watching this website. It's contents are transferred to your client from the "pen" server to your client using a protocol called "HTTP" (hypertext transfer protocol).
!What is "port"?