I‘ve an CentOS based server and Ubuntu based desktop pc. I’m connecting to my CentOS using ssh X11 forwarding feature. However, speed over the Internet is pretty slow for certain apps such as VMWare console. How do I speed up OpenSSH X11 forwarding using Linux / UNIX desktop system?
ow do I change my rsync command port number while making backup to remote server at backup1.example.com port 10253 (my ssh server runs on tcp port # 10253)? How do I change port number while using rsync command?
I need to provide a remote access to my Ubuntu Linux server. How do I start / stop OR restart the ssh server under Ubuntu Linux operating system?
Q. I’m moving my server from local data center to another data center. I’ve new server up and running. My site is dynmic and I’d like to transfer MySQL database from old server to new server. How do I make transfer smooth and successful?
A. The best and secure way is to use ssh to transfer database to another server. You need to use following tools:
=> SSH client
=> SSH Server on remote box
=> mysqldump command
=> UNIX pipes
Let us say you would like to Transfer MySQL database called foo to remote box called bar, enter the following command at shell prompt:
$ mysqldump foo | ssh [email protected] mysql foo
You can just copy table called chocolate (from recipe database) to remote database called icecream using same syntax:
$ mysqldump recipe chocolate | ssh [email protected] mysql icecream
Q. How do I block access to root user over ssh session?
A.. sshd (OpenSSH Daemon) is the daemon program for ssh. Server side ssh configuration is defined in /etc/ssh/sshd_config file.
You need to use DenyUsers option to block access to root user.
This option can be followed by a list of user name patterns, separated by spaces. Login is disallowed for user names that match one of the patterns. Only user names are valid; a numerical user ID is not recognized. By default, login is allowed for all users. If the pattern takes the form [email protected] then USER and HOST are separately checked, restricting logins to particular users from particular hosts.
Open /etc/ssh/sshd_config file
Use vi command:
# vi /etc/ssh/sshd_config
Deny root user access
Append or modify as follows to block root user:
If you want to block additional user just append names to DenyUsers
DenyUsers root, user2, user3
Save and close the file. Restart sshd service:
Q. Iâ€™ve HP-UX installed on my HP UX UNIX server. But Iâ€™m not able to start or restart the OpenSSH ssh server. How do I stop or restart sshd under HP-UX?
A. HP-UX Secure Shell uses Pluggable Authentication Module for password authentication. Server configuration file is located at /opt/ssh/etc/sshd_config.
HP-UX SSHD System Startup and Shutdown script:
System startup configuration file
Stop HP UX SSH Service
Type the command:
# /sbin/init.d/secsh stop
Start HP UX SSH Service
Type the command:
# /sbin/init.d/secsh start
Q. I have just installed Ubuntu 6.06 and I would like to allow remote login to my system from home via ssh. How do I install and configure SSH server?
A. OpenSSH is a FREE version of the SSH connectivity tools that technical users of the Internet rely on. Users of telnet, rlogin, and ftp may not realize that their password is transmitted across the Internet unencrypted, but it is. OpenSSH encrypts all traffic (including passwords) to effectively eliminate eavesdropping, connection hijacking, and other attacks. Additionally, OpenSSH provides secure tunneling capabilities and several authentication methods, and supports all SSH protocol versions.
Ubuntu SSHD Installation
Type the following two command to install both ssh client and server:
# sudo apt-get install openssh-server openssh-client
To be frank your server is ready by default. Just test it from your home computer or from same system with the command:
# ssh localhost
# ssh [email protected]
How do I use ssh client?
Assuming that your server hostname is userver.mydomain.com and username is vivek, you need to type the following command:
# ssh [email protected]
To stop ssh server, enter:
# sudo /etc/init.d/ssh stop
To start sshs server, enter:
# sudo /etc/init.d/ssh start
To restart ssh server, enter:
# sudo /etc/init.d/ssh restart