Technology Insights

RackSpace Cloud DNS Round Robin DNS A Records

I typically use Amazon’s AWS EC2 cloud services which include Route53 for DNS however I have certain clients that prefer RackSpace and therefore require RackSpace Cloud DNS services. One of the primary reasons for not just using an external DNS service such as Amazon’s Route53 DNS service is because when you setup large cloud deployments you typically are going to need internal DNS entries for communication between cloud instances and DNS services such as Route53 will not respond externally to RFC1918 or private IP space for those DNS entries. Anyhow one thing that is well documented or easy to accomplish on Route53 is creating A records with multiple IP’s for round robin DNS which provides a cheap easy to configure load balancing of sorts for different services such as MySQL. I could not find any documentation or mention of round robin DNS setup on RackSpace Cloud DNS so I wanted to explain how I was able to accomplish this.

Information Security

genlist – Backtrack – Miscellaneous – Miscellaneous Network – genlist

Clicking on the genlist menu item in Backtrack Linux opens a terminal window and outputs the genlist help menu at the top. Genlist is a Perl script written to provide an easy way to generate a list of live hosts on a network or set of networks so you can then begin analyzing those hosts. All the genlist Perl script does is call nmap with the -sP switch and parse the results so only the live IP addresses are output and as simple as it seems its a handy little tool if you do penetration testing on a regular basis. Below we describe genlist in more detail and show an example of genlist in action.

Technology Insights

Windows Virtual PC DNS Not Working Over Shared Networking NAT

Windows Virtual PC is pretty slick for having virtual machines on a Windows 7 computer. I use it for multiple Linux virtual environments including Backtrack and CentOS on a  regular basis. One issue you may run into is that your wireless network card will likely not work in Linux so you will be required to use shared networking (NAT) instead. Below is information on what you will need to do to get shared networking (NAT) operational in Backtrack Linux.

Information Security

Backtrack 4: Information Gathering: Route: Netenum – Produce lists of hosts for other programs

The next tool up for review is the netenum script. Netenum can be used to produce lists of hosts for other programs. It’s not as powerful as other ping-sweep tools, but it’s simple. When giving a timeout, it uses ICMP echo request to find available hosts. If you don’t supply a timeout, it just prints an IP address per line, so you can use them in shell scripts.

Technology Insights

How to Use MTR (Traceroute and Ping Combined)

One of the not so well know networking tools available on Linux is MTR.  MTR combines the functionality of the traceroute and ping programs in a single net-work diagnostic tool.  As mtr starts, it investigates the network connection between the host mtr runs on and a user-specified destination host. After it determines the address of each network hop between the machines, it sends a sequence ICMP ECHO requests to each one to determine the quality of the link to each machine. As it does this, it prints running statistics about each machine.   A sudden increase in packet-loss or response time is often an indication of a bad (or simply overloaded) link.  mtr is fairly easy to use once you have a look at the different options possible:

mtr-help-flags