Quick Steps in installing GNS3 on CentOS 6.4 x64

1. Login as root and run, (accept all dependencies)

yum install python python-devel xorg-x11-proto-devel libXext-devel gcc-c++ libXrender* PyQt4 PyQt4-devel qt qt-devel qemu-img libvirt

2. Download and extract the latest GNS3 and dynamips at http://www.gns3.net/download/

3. Rename the extracted folder to gns3 inside create a dynamips folder and cut and paste the latest dynamips. Right click and modify  file permission to Execute (check box allow executing file as a program)

4. move the gns3 folder to /opt directory 
   mv gns3 /opt

5. run as root: 
   cd /opt/gns3 
   [root@P5Q gns3]# python gns3

6. Create folder location for images, projects, working directory etc. Test Dynamips,Qemu and Vbox.

Dynamips settings