CentOS BIND DNS Not Responding To DNS Queries
KB ID 0000906 Problem While moving my DNS records from my old hosting company, I finally got round to pointing my domain name server records at my own server. I then saw my web traffic nose dive! Some troubleshooting steps later I realised I could not connect to my server on TCP port 53 (use an online port scanner to test yours). Solution Allow Access to DNS BIND From Remote Clients 1. Firstly let’s make sure that the firewall...
CentOS – Setup the iptables Firewall
KB ID 0000938 Problem I was a little perturbed to find out the firewall on my CentOS web server was wide open today. My server setup notes yielded no clues, so it was time to put my ‘Linux Head’ on and fix it. Solution 1. Connect to the server via console or SSH. As I’m going to change the iptables config file lets back it up (always assume you are going to smash something!) cp /etc/sysconfig/iptables iptables.bak 2....
CentOS 7 – No Network Connection
KB ID 0001047 Problem A while ago I spun up a CentOS server in VMware Workstation, and I could not get it connected to the network, I was in a bit of a hurry, so I blew it away and just built a new server with CentOS 6. This week I’ve been using VirtualBox and spun up a new CentOS 7 server and had the same problem. Solution 1. Quite why CentOS 7 does this I’m not sure, My NIC is called enp0s3 (run ‘ip addr’ to...
CentOS 7 – Ifconfig Command Not Found
KB ID 0001048 Problem Although not my strongest subject, I know enough to get by in Linux, so I was a little put out when I tried to run ifconfig, only to be told it could not be found. On an ‘out of the box’ install you are supposed to use ‘ip addr’ instead. Solution To Install Ifconfig 1. Run either of the following; yum provides ifconfig or yum whatprovides ifconfig And you should see a net-tools package....
Hacking Wireless WEP Keys with BackTrack and Aircrack-ng
KB ID 0000633 Problem Disclaimer: This article is for educational purposes only. Having the ability to pick a lock does not make you a thief. The main thing to take away from this article is, “DONT secure your wireless network with WEP”. WEP, has been around for a long time now, its limited to an alpha numeric password, 0-9 and A-F (because its in hexadecimal), the password can be 40, 64 or 126 bits long. The flaw is, each...
Installing the BackTrack Linux VMware Virtual Machine
KB ID 0000631 Problem I’m fortunate enough that VMware gave me a free copy of VMware Workstation, but there’s nothing to stop you carrying out this procedure with the FREE VMware player. BackTrack Linux is an operating system that is primarily used for security auditing, and penetration testing. I’m going to be playing with it a bit in the coming weeks, so I thought I’d at least document how to get it running....
Apache Web Server – Change the Default Page
KB ID 0000882 Problem Out of the box, Apache expects your website homepage to be called index, on this site the homepage is called home, here’s how to change it. Solution 1. Connect to the server via SSH, (or open a terminal session). The file you need to edit is called httpd.conf. This server is running CentOS, so you should find that file in the /etc/httpd/conf folder. 2. I’m going to edit it with nano. 3. Locate the...
Apache is Ignoring the .htaccess file
KB ID 0000890 Problem The .htaccess file is a file that lives in a directory on a web server. Its job is to provide ‘settings’ that would normally be set in the servers httpd.conf file. You can put a .htaccess file in any directory to control the settings for that directory, (providing .htaccess override has been allowed). After having some problems the other day, I made a change to mine, then reliased the change was not...
Webmin – Upgrade Error – ‘Perl (Net::SSLeay) is needed’
KB ID 0001100 Problem I like to keep my CentOS server updated as much as I can, but the last couple of times I’ve gone to run the upgrade of the Webmin console, I’ve got this; error: Failed dependencies: perl(Net::SSLeay) is needed by webmin (version) Solution 1. As error messages go this is not a bad one, it obviously needs perl installing. So SSH into the server and execute the following command; yum -y install perl...