CentOS (RHEL) Installing VMware Tools in ESX
KB ID 0000888 Problem This was a much more complicated job than I expected it to be! The following procedure is done on CentOS 6, so will be the same for Red Hat Enterprise 6. Solution 1. Connect to the server via SSH, (or open a terminal session). Logon as, (or su to) root. 2. Execute the following commands; yum install make gcc kernel-devel kernel-headers glibc-headers perl mkdir /mnt/cdrom 3. Then present the VMware tools CD to the...
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 – Install and Configure a TFTP Server
KB ID 0000998 Problem I needed to back up a Cisco firewall, and perform an upgrade remotely, despite my best efforts to use the ASDM and update via http, I had to go ‘old school’ and bring up a TFTP server on one of my CentOS Linux servers. Solution 1. Log onto the server and install the xinetd TFTP Server. Execute the following command and follow the on-screen prompts. Using username “root”. Last login: Thu...
CentOS – Disable BIND DNS Recursion
KB ID 0000981 Problem I got a Tweet this morning, to say the site was down. I checked and the VPS was off-line? So I powered it on and waited a few minutes. Linux is not one of my strongest technical areas so I did some Googling about what logs to check etc. When I looked in the var/log/messages log it was full of these, up to the point where it went down; Aug 7 03:51:52 MY-HOSTNAME named[490]: error (unexpected RCODE REFUSED)...
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...