This will be a simple step by step tutorial to help beginners catch up with ASTERISK - an open source tool for voice communication. It is a software installation of PBX connecting even the PSTN and VOIP networks. Originally developed for Linux, Asterisk now runs on a variety of operating systems including Solaris, Windows and MacOS. Environment setup (more…)

Migrating SSL certificates: CPanel, WHM Possible Scenarios i) Server load balancing ii) Moving web sites between servers Find where the SSL certificates, private keys are installed in the old server and gzip the certs $ tar -zxcf /tmp/crt.tar.gz /etc/ssl/certs $ tar -zxcf /tmp/priv.tar.gz /etc/ssl/private In the new server, extract the certificates and keys to its respective folder location. Edit httpd.conf file and add the following lines SSLEngine on SSLCertificateFile /etc/ssl/certs/example.com.crt SSLCertificateKeyFile /etc/ssl/private/example.com.key SSLCACertificateFile /etc/ssl/certs/example.com.cabundle CustomLog /usr/local/apache/domlogs/exampleuser-ssl_log combined Sample virtual host configuration setting

<VirtualHost xxx.xxx.xxx.xxx:443>
    ServerName subdomain.example.com
    ServerAlias www.subdomain.example.com
    DocumentRoot /home/emaple/public_html
    ScriptAlias /cgi-bin/ /home/example/public_html/cgi-bin/
    SSLEngine on
    SSLCertificateFile /etc/ssl/certs/example.com.crt
    SSLCertificateKeyFile /etc/ssl/private/example.com.key        
   SSLCACertificateFile /etc/ssl/certs/example.com.cabundle    
  CustomLog /usr/local/apache/domlogs/exampleuser-ssl_log combined
    SetEnvIf User-Agent ".*MSIE.*" nokeepalive ssl-unclean-shutdown
    <Directory "/home/example.com/public_html/cgi-bin">
        SSLOptions +StdEnvVars
    </Directory>

    # To customize this VirtualHost use an include file at the following location
    # Include "/usr/local/apache/conf/userdata/ssl/2/exampleuser/example.com/*.conf"
</VirtualHost>

Restart apache $ /etc/init.d/httpd restart (or) $ /sbin/service httpd restart Note: Once moving the SSL certificates to the new server, you can also use WHM or CPanel to configure the certs.

Check for the existence of the file sshd_config (/etc/ssh/sshd_config). Before editing the file check that path settings for sftp-server $ locate sftp-server /usr/libexec/openssh/sftp-server Check for the existence of following line in sshd_config Subsystem sftp /usr/libexec/openssh/sftp-server (more…)

Turn on warnings by use warning; To run a perl script with warnings, type -w with the shebang as in #!/usr/bin/perl -w print "Content-type: text/html\n\n"; print "Hello World\n"; Check if you have the following line in the program print "Content-type: text/html\n\n"; This will output the text to the browser from the server. Print error messages to the browser using use CGI::Carp qw(fatalsToBrowser); The other way is to use the print command to debug your program. Common error messages » The specified CGI application misbehaved by not returning a complete set of HTTP headers. » Can't locate missing-file.pm in @INC (@INC contains: ..... )

Full backup Full backup is process of backing up ALL data. First step towards all other types of backup Backup time will be longer Restore operation takes less time Differential backup Differential backup is the process of backing up data that has changed since the last FULL backup. Requires file maintenance as the backup file will be of similar size or larger than its previous backup Longer backup time than incremental backup Faster restoration than incremental backup Incremental backup Incremental backup is the process of backing up data that has changed since the last Full, Incremental or Differential backup Takes lesser backup time as it will have small data to archive Takes longer restoration time Mirror backup Mirror backup is similar to full backup and is a direct copy of the files/folders Files are not compressed in zip files and are not protected with password. They remain the mirror or exact copy of the source.

To display messages from the log $ cat /var/log/messages | more To show users who are logged in to the system $ who To show the list of users who have logged in last $ last To show the list of all reboots $ last reboot To print the content of the last login log from /var/log/lastlog $ lastlog