diff --git a/10_network_and_ssh.md b/10_network_and_ssh.md index f4b5c9c9c5d2532a7b3438d8c3eb72addcfe7f63..0ef51aa96b74675f65af7ca22e3c80e9c6500973 100644 --- a/10_network_and_ssh.md +++ b/10_network_and_ssh.md @@ -28,6 +28,8 @@ Packet switching is a method of grouping data over the network into packets. Eac  +In a packet switching network when you send a flux of data (video, sound, etc.), you have the illusion of continuity like for process switching handled by the scheduler. + ## **Internet Protocol** (IP) > The **Internet Protocol** (**IP**) is the principal [communications protocol](https://en.wikipedia.org/wiki/Communications_protocol) in the [Internet protocol suite](https://en.wikipedia.org/wiki/Internet_protocol_suite) for relaying [datagrams](https://en.wikipedia.org/wiki/Datagram) across network boundaries. Its [routing](https://en.wikipedia.org/wiki/Routing) function enables [internetworking](https://en.wikipedia.org/wiki/Internetworking), and essentially establishes the [Internet](https://en.wikipedia.org/wiki/Internet). @@ -94,9 +96,35 @@ UDP uses a simple [connectionless communication](https://en.wikipedia.org/wiki/C - Multicast (a single datagram packet can be automatically routed without duplication to a group of subscribers) - Lightweight (no ordering of messages, no tracking connections, etc. It is a very simple transport layer designed on top of IP) +### Port + +Higher, communication protocols like TCP and UDP, also define **port**. A **port** is a communication endpoint. When software wants to communicate overt TCP or UDP it will do so using a specific **port**. Each system has **port** numbers ranging from 0 to 65535. **Port** numbered from 0 through 1023 are system **ports** used by well-known processes (you need specific rights to use them). + +Here are a list of notable port numbers: + +| Number | Assignment | +| ------ | ------------------------------------------------------------ | +| 20 | [File Transfer Protocol](https://en.wikipedia.org/wiki/File_Transfer_Protocol) (FTP) Data Transfer | +| 21 | [File Transfer Protocol](https://en.wikipedia.org/wiki/File_Transfer_Protocol) (FTP) Command Control | +| 22 | [Secure Shell](https://en.wikipedia.org/wiki/Secure_Shell) (SSH) Secure Login | +| 23 | [Telnet](https://en.wikipedia.org/wiki/Telnet) remote login service, unencrypted text messages | +| 25 | [Simple Mail Transfer Protocol](https://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol) (SMTP) E-mail routing | +| 53 | [Domain Name System](https://en.wikipedia.org/wiki/Domain_Name_System) (DNS) service | +| 67, 68 | [Dynamic Host Configuration Protocol](https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol) (DHCP) | +| 80 | [Hypertext Transfer Protocol](https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol) (HTTP) used in the [World Wide Web](https://en.wikipedia.org/wiki/World_Wide_Web) | +| 110 | [Post Office Protocol](https://en.wikipedia.org/wiki/Post_Office_Protocol) (POP3) | +| 119 | [Network News Transfer Protocol](https://en.wikipedia.org/wiki/Network_News_Transfer_Protocol) (NNTP) | +| 123 | [Network Time Protocol](https://en.wikipedia.org/wiki/Network_Time_Protocol) (NTP) | +| 143 | [Internet Message Access Protocol](https://en.wikipedia.org/wiki/Internet_Message_Access_Protocol) (IMAP) Management of digital mail | +| 161 | [Simple Network Management Protocol](https://en.wikipedia.org/wiki/Simple_Network_Management_Protocol) (SNMP) | +| 194 | [Internet Relay Chat](https://en.wikipedia.org/wiki/Internet_Relay_Chat) (IRC) | +| 443 | [HTTP Secure](https://en.wikipedia.org/wiki/HTTP_Secure) (HTTPS) HTTP over TLS/SSL | + +Nowadays, **ports** provide multiplexing, which means that multiple service or communication session can use the same **port** number. + ## SSH -There exist numerous other protocols ([RTP](https://en.wikipedia.org/wiki/Real-time_Transport_Protocol) for example). But most of them run over the TCP and UDP protocols. **SSH** or **Secure Shell** is one of them. SSH is a [cryptographic](https://en.wikipedia.org/wiki/Cryptography) [network protocol](https://en.wikipedia.org/wiki/Network_protocol) for operating network services securely over an unsecured network. +There are numerous other protocols ([RTP](https://en.wikipedia.org/wiki/Real-time_Transport_Protocol) for example). But most of them run over the TCP and UDP protocols. **SSH** or **Secure Shell** is one of them. SSH is a [cryptographic](https://en.wikipedia.org/wiki/Cryptography) [network protocol](https://en.wikipedia.org/wiki/Network_protocol) for operating network services securely over an unsecured network. SSH use a client-server architecture, you use an SSH client to connect to an SSH server. By default most Linux distribution don’t comes with an SSH server installed. For the IFB, SSH connection is the default way to connect to your VMs, so you should have an SSH sever up and running. @@ -114,7 +142,7 @@ SSH uses [Public-key cryptography (or asymmetric cryptography](https://en.wikipe ### Public-key cryptography -SSH uses [Public-key cryptography (or asymmetric cryptography](https://en.wikipedia.org/wiki/Public-key_cryptography)), is a cryptographic system which uses pairs of [keys](https://en.wikipedia.org/wiki/Cryptographic_key): *public keys* (which may be known to others), and *private keys* (which may never be known by any except the owner). +[Public-key cryptography (or asymmetric cryptography](https://en.wikipedia.org/wiki/Public-key_cryptography)), is a cryptographic system which uses pairs of [keys](https://en.wikipedia.org/wiki/Cryptographic_key): *public keys* (which may be known to others), and *private keys* (which may never be known by any except the owner). A cryptographic algorithm is used to generate a pair of *public* and *private* keys from a large random number. Then, the 3 following scheme can be used to secure communication: @@ -140,7 +168,7 @@ Can be used to share public keys (see [Diffie-Hellman)](https://fr.wikipedia.org ## SSH Server -By default, on the IFB, password authentication is disabled to enforce the use of public key based authentication. To learn `ssh` command we are going to enable this option on your VMs. Find their `sshd` configuration file and open it with an editor of your choice. +By default, on the IFB, password authentication is disabled to enforce the use of public key based authentication. To learn `ssh` command we are going to enable this option on your VMs. Find the`sshd` configuration file and open it with the editor of your choice. <details><summary>Solution</summary> <p> @@ -358,4 +386,14 @@ Host work-ens PreferredAuthentications publickey,password, ``` -With the command `ssh work-ens`, the `ssh` client is going to first connect to `ens` and then from `ens` to the `ip.ip.ip.ip` server. \ No newline at end of file +With the command `ssh work-ens`, the `ssh` client is going to first connect to `ens` and then from `ens` to the `ip.ip.ip.ip` server. + +In the next session, we are going to learn how to [install system-wide programs](http://perso.ens-lyon.fr/laurent.modolo/unix/11_install_system_programs.html) like the one managed by `systemd` + +> We have used the following commands: +> +> - ssh to establish ssh connection +> - sytemctl to manage system daemons +> - scp to copy files +> - rsync to copy files + diff --git a/Makefile b/Makefile index 7d5af6a238dde4fea113b163a08620118d406ac8..17d1350900b513bfd6703eba67593e8dff59b7e3 100644 --- a/Makefile +++ b/Makefile @@ -8,7 +8,8 @@ all: html/index.html \ html/7_streams_and_pipes.html \ html/8_text_manipulation.html \ html/9_batch_processing.html \ - html/10_network_and_ssh.html + html/10_network_and_ssh.html \ + html/11_install_system_programs.html html/index.html: index.md github-pandoc.css @@ -43,3 +44,6 @@ html/9_batch_processing.html: 9_batch_processing.md github-pandoc.css html/10_network_and_ssh.html: 10_network_and_ssh.md github-pandoc.css pandoc -s --toc -c github-pandoc.css 10_network_and_ssh.md -o html/10_network_and_ssh.html + +html/11_install_system_programs.html: 11_install_system_programs.md github-pandoc.css + pandoc -s --toc -c github-pandoc.css 11_install_system_programs.md -o html/11_install_system_programs.html diff --git a/index.md b/index.md index 622c138ba0fbc8279dfa5b7eaa0a4ca6e767cc3c..170de982b67afd356d87f53729b295b56f39fba8 100644 --- a/index.md +++ b/index.md @@ -14,5 +14,6 @@ title: # Unix / command line training course 8. [Text manipulation](http://perso.ens-lyon.fr/laurent.modolo/unix/8_text_manipulation.html) 9. [Batch processing](http://perso.ens-lyon.fr/laurent.modolo/unix/9_batch_processing.html) 10. [Network and ssh](http://perso.ens-lyon.fr/laurent.modolo/unix/10_network_and_ssh.html) +11. [Install system-wide programs](http://perso.ens-lyon.fr/laurent.modolo/unix/11_install_system_programs.html)