What is the difference between authentication and authorization? Why it is important to understand difference between the two? Authentication vs. Authorization — what are they and how do they differ?
Q. I’ve couple of Linux / Windows server hosted in remote data center? My ISP provides following option for rebooting the box:
a) Graceful shutdown command
b) An IPMI reboot
c) A power strip
Which one is the best way to reboot server and why?
Continue reading “Best Method To Reboot Remote Linux / Windows / UNIX Server”
Continue reading “OpenBSD Set Date and Time Command”
Q. One of my responsibilities is backing up UNIX server. How do I backup data under HP-UX UNIX? How do I use mt, fbackup and frecover commands to perform full and incremental backups?
Continue reading “How to: HP-UX UNIX Backup and Recover Data to Tape Device”
Q. How do I install and turn on telnet server on Debian Linux VPS Server?
A. I don’t recommend using telnet at all on VPS or any other Linux / UNIX server. Telnet transfers all data including passwords in clear text format. It is recommended that you use ssh which is installed by default.
Use ssh and connect to remote server called boo.myvps.com, enter:
In case you still need telnet, type the following two commands (not recommended
# apt-get install telnetd
# /etc/init.d/inetd restart
$ telnet server-ip-address
Q. I’ve HP-UX installed on my HP UX UNIX server. But I’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. How do I find out the memory size of my AIX UNIX server? Can you tell us the command name to do the same?
A. You need to use bootinfo command to determines and displays various boot information, including boot device type and boot device name.
Command to check RAM in AIX UNIX
The bootinfo command uses the device configuration databases in information searches.
Just type the following command as the root user:
It will displays amount of real memory in kilobytes. bootinfo command may not be available in latest AIX UNIX version, try following command:
$ lsattr -El sys0 | grep realmem
svmon command – Captures and analyzes a snapshot of virtual memory
The svmon command displays information about the current state of memory. The displayed information does not constitute a true snapshot of memory, because the svmon command runs at user level with interrupts enabled. To print out global statistics, type:
# svmon -G
Read the man page of svmon for more information.