Technology Insights

iPhone Visual Voicemail Not Working With iOS Beta 6

I updated my iPhone to iOS Beta 6 a couple weeks back and ever since I have not been receiving visual voicemail notifications. Initially I thought people were just not leaving me voicemails but once I finally called into voicemail by holding the number one on my iPhone keypad to check voicemail I realized I had 25 voicemails. Once they were all cleared out I moved on the trying to fix the visual voicemail issue which turns out is really easy to resolve by following the below steps.

Technology Errors

Snort Configure Error: ERROR! dnet header not found – CentOS Linux

Earlier when installing snort on a CentOS Linux server I ran into a configure error. The error related to the fact that libdnet was not located on the server and while it was installed I did not have the libdnet-devel package installed. Below is the sample output from the configure error, an expandable complete output of the configure error, and the yum command to install libdnet-devel to move past this error when installing snort.

Technology Insights

List All IP Addresses Making Port 80 Connections To Linux Server

Earlier while analyzing a Linux server it was pointed out to me that the Apache logs were filling up with constant connections requesting domains that were not configured on the server. To me it looked as if a load balancer somewhere was misconfigured and sending traffic to our IP address by mistake but I needed to open a ticket with the colocation provider to have them look into the issue further since the network in this case is not something I have any control over. Below is a quick Linux command that will output a list of IP addresses making port 80 connections to your server.

Code Snippets

RightScale RightScript To Add SSH Users To Linux Nodes On Boot

The below code snippet was used to add SSH users to RackSpace cloud CentOS Linux nodes being used as application servers and managed via RightScale. The SSH users were required during a testing phase so they could look through logs and make modifications to specific configuration files, etc. There are three things that have to happen to create the SSH user, allow them to login, and provide them the necessary rights on the server to accomplish their tasks which include adding the user, modifying the sshd config to allow password logins, and update the sudoers file to enable sudo access for wheel group users.

Code Snippets

Restart Services On RackSpace Managed Nodes That Require sudo Rights

Recently I was working on a project that was using RightScale to manage RackSpace cloud nodes. One of the requirements of the project was to have application nodes scale automatically thus they were required to automatically install software, configure settings, and start services automatically on the RackSpace CentOS nodes being used. Most everything was fairly straight forward however some of the services we were using would not start properly and initially because of the lack of logging from the services we were unable to figure out what the problem was. Below I describe the problem in more detail along with the solution which involved updating a configuration file on the CentOS Linux servers and then restarting the services.