This is the second part of the series that consolidates all articles about GNS3 labs in the Intense School website. (Part one, featuring 24 more GNS3 labs, can be found here.)

The GNS3 labs presented here offer a diverse collection of topics that span multiple technologies at various complexity levels. All labs contain downloadable GNS3 config and topology files to get you started.

The labs are grouped per technology: security, routing and miscellaneous. In the last category, there will be labs that are neutral with regards to security or routing topics.

Routing Topics

Let’s start with the basic topics in the routing section. There is a pack of videos, each around 10 minutes long, that demonstrate the concepts while also utilizing GNS3 labs.

One of these videos is from the article CCNA Prep Video 200-120 Exam – Interface Configuration Part 2 which shows how to configure interfaces and how to verify the operation. Introduction to IP Routing will help you practice static routing. The last article from the videos pack is Cisco IOS Privilege Levels, where you can practice IOS privilege levels and configure users with different privilege levels.


There is a pack related to OSPF composed of four articles: OSPF Area Types, which shows how you can configure the five types of OSPF areas; OSPF Route Filtering, which shows how to filter routes in OSPF using distribute-lists along with route-maps and ACLs; and OSPF Authentication Under IPv4 and IPv6 and OSPF Authentication with GNS3, which both focus on OSPF authentication for both IPv4 and IPv6.


Another interesting pack is the one dealing with multicast. There are again four articles: Introduction to IPv4 Multicast, an introduction to what multicast is and how to configure PIM; Auto-RP, which shows how to configure the Cisco proprietary Auto-RP as a way to distribute RP information; Multicast Boot Strap Router, which shows how to advertise information about the RP in a multicast domain using the vendor independent feature of BSR; and Basic MSDP, which shows how to configure MSDP in case you have IPv4 RPs that need to be advertised and would like to use a single IP address as RP configured on multiple devices for increased redundancy.

Security Topics

Next, the security section follows and it’s the largest one. One interesting pack is about VPNs bridging and the different methods to do this. The article Bridging VPNs Part 1 shows how to accomplish this by configuring a hub-and-spoke topology.

The next part of the series, Bridging VPNs Part 2, shows how to bridge two VPN sites by using Virtual Tunnel interfaces.

The third part called Bridging VPNs Part 3 (DMVPN) will show you how two sites can have reachability between them through a third site using DMVPN (Dynamic Multipoint Virtual Private Network).

The final part of the series called Bridging VPNs Part 4 (Cisco ASA) shows how to bridge two VPN sites through a third VPN site on Cisco ASA devices.

VPN Tunnels

The bridging VPN pack is continued with a series of articles related to high availability and redundancy achieved through VPN tunnels. The series is opened with the article Using VPN Tunnels as Backup Links: Static Routes and IP SLA Tracking, which shows how a site can have a backup link by using static routes whose status is tracked by IP SLA (Service Level Agreement).

The next article is Using VPN Tunnels as Backup Links: VTI and Dynamic Routing, where the same redundancy will be achieved by using Virtual Tunnel Interfaces (VTI) on top of which the routing protocols can run and recover in case of failure.

The last article of the series, Using VPN Tunnels as Backup Links: Primary and Backup VPN Tunnels on Cisco ASA, lets you see how to deploy an active/backup VPN configuration on Cisco ASA by using static routes and crypto maps along with SLA for failure detection.

Site-to-Site VPN

Another series containing three articles is about Site-to-Site (L2L) features. The first article of the series, L2L VPN on Cisco ASA with Overlapping Addresses – Access to Both ASAs, shows how to configure site-to-site VPN between two Cisco ASAs that have the same IP addressing in the LAN through the means of NAT.

The second part, L2L VPN on Cisco ASA with Overlapping Addresses – Access to One ASA, shows how to achieve the same goal but with the restriction that the access be available only to one Cisco ASA and the method used to achieve this is by using source/destination NAT.

The last part, Filtering Traffic in L2L VPN on Cisco IOS Router, shows how to filter traffic inside the site-to-site VPN tunnels using the set ip access-group command.


The next series deals with Border Gateway Protocol (BGP) on Cisco ASA. The first article Configuring BGP through Cisco ASA shows how to configure the Cisco ASA so that two BGP peers can form a BGP adjacency through the ASA device. Also, issues that might appear with BGP authentication when the BGP session has to transit the Cisco ASA are discussed.

The second part of the series, Configuring BGP on the Cisco ASA, shows how to configure BGP on the Cisco ASA as well as other features that can help implement BGP policies to alter the best path selection algorithm.

One interesting article in this category is Dynamic Site-to-Site VPN on Cisco ASA where you can learn how to create a VPN tunnel between a router with a dynamically allocated IP address and a Cisco ASA with a static IP address.

The last article that is part of this collection is Internet Access via Cisco VPN Remote-Access Tunnel and it will demonstrate how to allow VPN users to connect to the internal network behind the Cisco ASA and also access the Internet via a VPN tunnel.

Miscellaneous Topics

The next section is about GNS3 labs that do not fall in either the routing or security categories. The section has one lab, Cisco – Linux Integration: Dynamic Routing, where you can see how to do interoperability between Cisco devices and Linux.

Another article that falls in this section is Quality of Service Configuration and Verification, where you will see how to configure class-maps and policy-maps to achieve Modular QoS.

The last article of this section is CCNA Voice Labs in GNS3 with VTGO-PC Multilab, which, as you might have figured out, is oriented on CCNA Voice and shows you how to use VTGO-PC Multilab software that allows you to instantiate multiple soft phones on the same computer.

And that’s it. A comprehensive collection of GNS3 labs that will help you speed up the hands-on process and provide you guidance on how to configure different security and routing features. I hope you enjoyed these and that they helped you to understand these concepts a little better!