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Statefull NAT64 – simple configuration example on Cisco routers

The example shows a simplified configuration of a Statefull NAT64 demo, without DNS64. I instruct the stateful NAT64 router (CSR-1 – CSR100v) to translate IPv6 packets into IPv4 packets (and vice versa) using algorithmic mapping (defined by RFC 6052) of IPv4 addresses of IPv4 routers to and from IPv6 addresses by using manually defined IPv6 prefix 2001:db8::/96). In a similar manner, the IPv6 addresses of IPv6 routes are translated to and from IPv4 addresses.


R1/R2 run 7200 IOS image., R1 is pure IPv4 router, on the other site, R2 is IPv6 only.

How to later integrate Solar-Putty with GNS3 as the preferred console application

Starting the GNS3 version 2.1.10, Solar-Putty is packaged as the default SSH client. However, how to integrate it to GNS3 later? As it was not selected during the GNS3 installation? Follow:

1. Download the Solar Putty application from Puty is zipped, therefore after the download has completed, unzip the Solar-PuTTY.exe application file to your preferred application folder. I used the C:\Program Files (x86)\Solar-Putty\ for that.

Multi tabbed, multi execution telnet/ssh client

Working on our practical networking lessons our students and I, as their teacher, we are usually configuring several routers and switches (sometimes up to ten), which are accessible remotely. For this, we welcome the use of multi-tabbed and especially multi execution clients.

They allow us to eficiently organize working space and run commands in one task on all connected network equipments (for example to save running config).

How to easily add Open vSwitch to GNS3

Open vSwitch (OVS) is a multilayer (MLS) virtual switch licensed under the open-source Apache 2.0 license which is widely used in the field of virtual networking. With this open-source MLS switch, we can easily extend GNS3 switching capabilities. We can add this switch to GNS3 very quickly using a GNS3 OVS appliance. No base Linux system VM is required, no ISO images.

In this post I’m going to describe how to add and run OVS MLS inside of the GNS3 (local or remote).

Using tcpdump for SIP diagnostics

TCPdump is a powerful command-line packet analyzer, which may be used for a SIP message sniffing/analyzing. TCPdump is preinstalled on many linux distributions, or may be installed directly from debian repository:

apt-get install tcpdump

TCPdump allows write sniff to a file or display it realtime. Its usage for SIP message analysis may look like:

Juniper vSRX as a router

The Juniper vSRX firewall can be operated and configured as a router. The reasons may be various, the use in GNS3 may include that vSRX has a smaller memory footprint or non-separated data and control plane. So. to do this, you must :

set system host-name ABC
set system root-authentication plain-text-password PASSWORD

And then change the packet processing mode from flow-based to packet-based: