FAQforge provides answers for frequently asked questions for the Linux-, MAC and Windows operating systems.

How to set a VNC password

Friday, March 20, 2015 - posted by admin

The Linux VNC server provides a command to set a new password. The command is "vncpasswd", the password is stored in encrypted form into the file ~/.vnc/passwd of the home directory of te user. Run:

vncpasswd

to set a new password for the currently logged in user. The command will then prompt for the new password. If you like to set a new VNC password for a different user, then append the password file name to the command. Example for the user "jane":

vncpasswd /home/jane/.vnc/passwd

The above command to set a new password for jane requires it that you are logged in as root user. On Ubuntu systems you can use sudo instead:

sudo vncpasswd /home/jane/.vnc/passwd

How to clear bash history

Thursday, March 19, 2015 - posted by admin

The Bash hisrory on a linux system is stored in the file .bash_history of the home directory of the user. To clear the history for the currently logged in user, run these commands:

cat /dev/null > ~/.bash_history
history -c

If you like to clear the history of a different user, use these commands. In the example I will cler the history for a user named tom:

cat /dev/null > /home/tom/.bash_history

Please note that you have to be logged in as root user to cler the Bash history of another user or use sudo to execute the command.

sudo cat /dev/null > /home/tom/.bash_history

Here is a list of ports that are used commonly on ISPConfig 3 servers. If you dont have all services installed or if you e.g. dont want to connect to MySQL from external servers, then close the unused or unwanted ports.

TCP ports

20 - FTP Data
21 - FTP Command
22 - SSH
25 - Email
53 - DNS
80 - HTTP (Webserver)
110 - POP3 (Email)
143 -Imap (Email)
443 - HTTPS (Secure webserver)
993 - IMAPS (Secure Imap)
995 - POP3S (Secure POP§)
3306 - MySQL Database server
8080 - ISPConfig web interface
8081- ISPConfig apps vhost

UDP ports

53 - DNS
3306 - MySQL

The Following command can be used to check and repair all MySQL databases on a Ubuntu or Debian Linux System.

Ubuntu Linux

sudo mysqlcheck --defaults-file=/etc/mysql/debian.cnf --auto-repair --optimize --all-databases

Debian Linux

mysqlcheck --defaults-file=/etc/mysql/debian.cnf --auto-repair --optimize --all-databases

The benefot of the above comand is that it uses the debian-sys-maint login to MySQL which is available on every Debian and Ubuntu System, so you dont have to provide the MySQL root login details.

How To Disable Error Logging For A Website In ISPConfig 3

Friday, August 8, 2014 - posted by admin

To disable the error.log for a website in ISPConfig on a Apache webserver, follow this steps:

1) Login to ISPConfig

2) Go to the website settings of the website were you like to disable the error.log and there go to the "Options tab"

3) Add the following line in the field labeled "Apache Directives"

ErrorLog /dev/null

and press save:

 

How to Copy Files with SCP between Linux Servers

Saturday, July 19, 2014 - posted by Till

1.1 SCP Command Line-An Overview

 

The SCP command line is commonly used to copy files over SSH, and between popular Operating systems like Linux, Mac and Windows in a secure fashion. SCP is used to copy files to/from a remote server. It also allows you to copy files from one remote server to another remote server, without passing traffic through your PC.

Solution for: system-config-firewall: command not found

Wednesday, February 5, 2014 - posted by admin

When you get the error message "system-config-firewall: command not found" on your CentOS Server while trying to configure the firewall on the shell, then the text interface version of the firewall configuration utility is missing. Install it with this command:

yum install system-config-firewall-tui

If your mail server stops working (neither incoming nor outgoing email works) and you find the following error message in the mail.log file:

fatal: open database /var/lib/postfix/smtpd_scache.db: File exists

then the smtpd_scache.db might got corrupted. Postfix will recreate this file, if it does not exist. So it can be removed to solve the issue:

/etc/init.d/postfix stop
rm -f /var/lib/postfix/smtpd_scache.db
/etc/init.d/postfix start

Thanks to Alexander Fox for sending me this FAQ.

Enable virtualization on Gigabyte Z77X-UDH3 motherboard BIOS

Monday, October 7, 2013 - posted by CSch

To enable virtualization on a machine with a Z77X-UDH3 motherboard run the BIOS by hitting Del while booting the computer.

Once inside click on the BIOS Features tab and look for the Intel Virtualization Technology entry. If it's set on Disabled, set it on Enabled. Afterwards save the changes made to your settings and quit the BIOS using the last tab from the main tab-line.

Virtualbox: VT-X is not available

Thursday, October 3, 2013 - posted by CSch

In some cases when you try to get a virtual machine running with Virtualbox or similar virtualization software you will get an error stating that 'VT-X is not available'. This relates to BIOS settings which, depending on your processor, determine whether your computer is able to virtualize stuff. These settings are not set automatically however, so it's worth a look into your BIOS whether you can actually change the setting and if your processor allows it.

The keyword to look for in the settings is 'Virtualization', it's probably placed in some advanced tab if there are some of those in your BIOS.

To see how it's done with a Z77X-UDH3 motherboard by Gigabyte see this post: Gigabyte Z77X-UDH3