Configure Postfix for SASL Authentication from Dovecot
KB ID 0000883 Problem I built a Postfix mail server with Dovecat on CentOS 6.4 installed last week. To read my emails I installed SquirrelMail on the same server, and surprisingly it all went well. However If I attempted to send mail from Microsoft Outlook on my laptop, or from my iPhone this happened; The following recipient(s) cannot be reached: ‘name@domain-name.com’ on 22/11/2013 22:21 Server error: ‘554...
Linux – Enable PHP Short Tags
KB ID 0000886 Problem I have a particular web page that uses PHP short tags. Post migration from my old hosting company to a dedicated VPS, this stopped working. As I know little about Linux, and even less about PHP, I asked the question at Experts Exchange about why It was no longer working. I took no time at all, for someone who knew what they were doing to say, “Your code uses ‘Short tags’, but you do not have...
Backing up a Remote Linux Machine With Windows (Using Rsync and Cygwin)
KB ID 0000892 Problem The goal here was for me to get a backup of my VPS server (Running CentOS 6). My background is primarily Windows based, so I wanted a solution where I can just run the backup from a Windows machine, (i.e. my my laptop) and let it connect, login and perform the backup. What is Rsync? If you are familiar with Robocopy it’s similar, it can perform a backup/sync of data and encrypt that data while it’s...
Postfix – Change The ‘Welcome Banner’
KB ID 0000907 Problem After my recent DNS troubles, I was checking my mail server’s (MX) records, and got a warning about not having any reverse lookup records (PTR) configured properly. I telnetted to the mail server on port 25, and saw it was responding with the servers host-name. I know my records are correct for the FQDN of the server, I just needed to change its welcome banner. Solution Change the Postfix Welcome Banner by...
Dropbox – Windows, Linux, Apple and Dropbox Portable (USB) Installation
KB ID 0000409 Problem You would like to sync your files/folders between more than one machine? Dropbox, is a service that lets you keep files in “The Cloud” and synchronise them across multiple machines and platforms. It’s one of those things that once you start to use it you wonder what you did before you had it. Simply put it’s like having a USB drive that you don’t need to carry around with you, and...
Connecting Evolution Mail Client to Exchange 2010 (and Exchange 2007)
KB ID 0000378 Problem Out of the box Evolution can only connect to Exchange 2000 and Exchange 2003, this is because it uses OWA to connect, when Exchange 2007 was released, the way OWA was presented changed a great deal. So if you try and connect to a newer version of Exchange it will error. (Before you email in, I know in 2010, its now called Web App not OWA). But there’s nothing to stop you connecting to Exchange 2007 and...
GNS3 – Assign an IP Address to Linux Microcore QEMU Guest
KB ID 0000932 Problem The whole point of having these guest machines is for testing communications, putting an IP address on them so you can ping things, is a pretty basic step. Solution 1. Console in, and execute the following commands, obviously change the IP addresses to the ones you require. sudo su ifconfig eth0 10.10.10.10 netmask 255.0.0.0 up route add ip default gw 10.10.10.1 route add default gw 10.10.10.1 Related Articles,...
Cisco ASDM – Accessing with Ubuntu
KB ID 0000396 Dtd 11/02/11 Problem Even though I prefer to use command line, there are times I need to manage Cisco firewalls from the ASDM. To do this from my Netbook running Ubuntu 10.10 it was not as straight forward as I was used to. Solution In my scenario I’m using Ubuntu 10.10 Desktop Edition, Chrome as my browser, and the ASDM is running version 6.3(1). 1. Before we start I’m assuming you know what the ASDM is and...
Linux (CentOS) Securing and Hardening SSH / Shell Access
KB ID 0000881 Problem The following is by no means an extensive list of everything that can be done. It’s just a run though of what I would consider ‘good practice’. Solution Create a user for SSH and Remove Shell access for the ‘root’ user. 1. Connect to the server via SSH or open a terminal session and su to root. Create a new user then set and confirm the new users password. useradd {username} passwd...
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...