≡ Menu

Advanced ( Expert) Linux / Unix System Administrator

These tutorials assumes that you have rock solid understanding of Unix like operating systems and very comfortable with most aspects of the Unix/Linux such as networking/distributed computing environments,routing, firewalls, servers, client/server programming, and the design of consistent network-wide filesystems, load-balancers, security and much more. ( rss feed )

OS X Mountain Lion 10.8 Set Apache and PHP Web-Server

I am using Apple OS X Mountain Lion 10.8.4 on my Macbook pro. For my school project I need to write an app in PHP 5 and Apache. However, I am unable to find the Web Sharing option from the Sharing panel in System Preferences. How do I install Apache and PHP5 in OS X version 10.8.4? How do I enable HTTPD and test my web app?
[click to continue…]

{ 7 comments }

Nginx: SPDY SSL Installation and Configuration On a Debian / Ubuntu Linux

Google Chrome/Chromium, Firefox and Opera browser support SPDY networking protocol. It enables faster browsing on supported sites. SPDY is similar to HTTP, with particular goals to reduce web page load latency and improve web security. SPDY achieves reduced latency through compression, multiplexing, and prioritization. How do I enable nginx SPDY support running on Debian or Ubuntu Linux server?
[click to continue…]

{ 4 comments }

Debian Linux: Upgrade v6.0.x Squeeze to v7.0.0 Wheezy

Recently Debian Linux version 7.0 (“Wheezy”) released. This version shipped with many new features – improvements to multimedia support, improved security through hardening flags and the OpenStack suite and the Xen Cloud Platform to name a few. How do I upgrades from Debian Linux version 6.x.x (squeeze) to the latest version 7.0.0 wheezy using command line options? How do I upgrade my Debian 6.x server to 7.x over the ssh session?
[click to continue…]

{ 11 comments }

Linux WARNING: Duplicate VG name server1 LVM2 Error and Solution

I recently added SSD to my home server and reloaded the operating system. However, when I try to access my dm-crypt based old disk, I am getting the following error:

Reading all physical volumes. This may take a while...
WARNING: Duplicate VG name server01: Existing bc7YA8-eEXt-1aA1-OHTr-zJkA-ucd0-DsbRTc (created here) takes precedence over RIKiar-w3MG-Gzh5-VFWq-bkRT-9IFc-ia8k87
WARNING: Duplicate VG name server01: Existing bc7YA8-eEXt-1aA1-OHTr-zJkA-ucd0-DsbRTc (created here) takes precedence over RIKiar-w3MG-Gzh5-VFWq-bkRT-9IFc-ia8k87
Found volume group "server01" using metadata type lvm2
Found volume group "server01" using metadata type lvm2

The problem is my volume group. I set to to server01 on both old and new hard disk. How can I rename old LVM2? How do I access my old hard disk?
[click to continue…]

{ 5 comments }

Debian / Ubuntu: Set Port Knocking With Knockd and Iptables

My iptables based firewall allows only port TCP 80 and 443. I also need tcp port # 22, but I do not have static IP at my home. How do I open and close TCP port #22 on demand under Debian or Ubuntu Linux based server systems? How do I install a port-knock server called knockd and configure it with iptables to open tcp port #22 or any other ports?

[click to continue…]

{ 3 comments }

Nginx: Block URL Access (wp-admin/wp-login.php) To All Except One IP Address

I am the small business owner and runs my own web-site. I have noticed increased cracking activity against by blog. What’s the best way to block WordPress URLs such as example.com/blog/wp-login.php and example.com/blog/wp-admin/ in the nginx web-server?
[click to continue…]

{ 4 comments }

Linux Iptables Setup Firewall For a Web Server

I have setup an Apache web server on CentOS Linux. How do I configure firewall to allow or block access? How do I setup firewall for a web server under RHEL or CentOS Linux v6.x?
[click to continue…]

{ 8 comments }