![OpenSSH: Secure Remote Shell
Secure replacement for older remote-access tools
Allows authenticated, encrypted access to remote systems
ssh [user@]hostname
ssh [user@]hostname command
ssh vmintam@localhost
ssh vmintam@localhost ‘who’](https://image.slidesharecdn.com/unit13networkclient-120309015114-phpapp01/85/Unit-13-network-client-7-320.jpg)
![scp: Secure File Transfer
Secure replacement for rcp
Layered on top of ssh
scp source destination
Remote files can be specified using:
[user@]host:/path/to/file
Use -r to enable recursion
Use -p to preserve times and permissions
Use -C to compress datastream
Example: scp –r /etc/* vmintam@localhost:/home/vmintam](https://image.slidesharecdn.com/unit13networkclient-120309015114-phpapp01/85/Unit-13-network-client-8-320.jpg)
![OpenSSH Key-based Authentication
Optional, password-less, but still secure, authentication
Uses two keys generated by ssh-keygen:
private key stays on your system
• Usually passphrase -protected (recommended )
public key is copied to destination with ssh-copy-id
ssh-copy-id [user@]host](https://image.slidesharecdn.com/unit13networkclient-120309015114-phpapp01/85/Unit-13-network-client-10-320.jpg)
Unit 13 network client
- 1. RedHat Enterprise Linux Essential Unit 13: Network Clients
- 2. Objectives Upon completion of this unit, you should be able to: Browse the web Exchange email and instant messages Access a Linux system remotely Transfer files between systems Use network diagnostic tools
- 3. Web Clients Firefox Other web browsers (chrome, IE ? ) Non-GUI web browsers (links ) wget
- 4. wget Retrieves files via HTTP and FTP Non-interactive - useful in shell scripts Can follow links and traverse directory trees on the remote server - useful for mirroring web and FTP sites wget http://mirror-fpt-telecom.fpt.net/centos/5.6/isos/i386/CentOS-5.6-i386- LiveCD.iso wget –bc –o /tmp/monitorwget.log http://mirror-fpt- telecom.fpt.net/centos/5.6/isos/i386/CentOS-5.6-i386-LiveCD.iso wget --tries=50 --wait=30 https://calomel.org/bootable_openbsd_cd.html wget --recursive --level=1 --convert-links http://vef.vn
- 5. Email and Messaging Evolution Other email clients ( thunderbird, Msoutlook ? ) Non-GUI email clients (mutt) Gaim
- 6. Gaim Multi-protocol Instant messaging client Available in Red Hat Enterprise Linux Client Supports AIM, MSN, ICQ, Yahoo, Jabber, Gadu-Gadu, SILC, GroupWise Messenger, IRC and Zephyr networks. Plugins can be used to add functionality.
- 7. OpenSSH: Secure Remote Shell Secure replacement for older remote-access tools Allows authenticated, encrypted access to remote systems ssh [user@]hostname ssh [user@]hostname command ssh vmintam@localhost ssh vmintam@localhost ‘who’
- 8. scp: Secure File Transfer Secure replacement for rcp Layered on top of ssh scp source destination Remote files can be specified using: [user@]host:/path/to/file Use -r to enable recursion Use -p to preserve times and permissions Use -C to compress datastream Example: scp –r /etc/* vmintam@localhost:/home/vmintam
- 9. rsync: Efficient File Sync Efficiently copies files to or from remote systems Uses secure ssh connections for transport rsync *.conf localhost:/home/vmintam/configs/ Faster than scp - copies differences in like files rsync /var/log/* vmintam@localhost:/home/vmintam/rsync
- 10. OpenSSH Key-based Authentication Optional, password-less, but still secure, authentication Uses two keys generated by ssh-keygen: private key stays on your system • Usually passphrase -protected (recommended ) public key is copied to destination with ssh-copy-id ssh-copy-id [user@]host
- 11. OpenSSH Key-based Authentication continued An authentication agent stores decrypted private keys Thus, passphrase only needs to be entered once An agent is provided automatically in GNOME Otherwise, run ssh-agent bash Keys are added to the agent with ssh-add
- 12. FTP Clients CLI: lftp $ lftp ftp.example.com $ lftp -u joe ftp.example.com Automated transfers with lftpget GUI: gFTP Applications->Internet->gFTP Allows Drag-and-Drop transfers Anonymous or authenticated access Optional secure transfer via ssh (sftp)
- 13. smbclient FTP-like client to access SMB/CIFS resources Examples: smbclient -L server1 lists shares on server1 smbclient -U student //server1/homes Smbclient 192.168.1.1Setup –U vmintam accesses a share
- 14. Xorg Clients All graphical applications are X clients Can connect to remote X severs via tcp/ip Data is not encrypted but can be tunneled securely over an ssh connection • ssh -X user@hostB xterm xterm will display on hostA's X server Transmitted data will be encrypted through the ssh connection
- 15. Network Diagnostic Tools ping traceroute host dig netstat