≡ Menu

Advanced

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…]

Sysadmin because even developers need heroes!!!

{ 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 }

Linux Configure Firewall Using Shorewall Under RHEL / CentOS

A properly configured firewall can greatly increase the security of RHEL / CentOS based system. How do I configure a shorewall based firewall for CentOS or Red Hat Enterprise Linux system with an Internet connection? How do I install and configure shorewall to protect the following small business network?

[click to continue…]

{ 3 comments }

CentOS / RHEL: Install ipset Administration Tool For IP Sets and IPTables

How do I install the ipset extension to Netfilter/iptables on Red Hat Enterprise Linux / CentOS Linux v6.x?
[click to continue…]

{ 3 comments }

MySQL/MariaDB Server: Bind To Multiple IP Address

I have MySQL/MariaDB database system running on a FreeBSD/Linux server. The server has multiple ip address. The mysqld used by many websites hosted on two other CentOS Linux based servers. I would like to bind MySQL sever running on a Linux or Unix-like server to more than one IP address such as 202.54.1.2, 202.54.1.10, and 202.54.1.15. How can I bind mysqld to multiple ips?
[click to continue…]

{ 8 comments }