Category Archives: Tools

Google BBR Algorithm

Google’s BBR algorithm for handling TCP traffic congestion could announce a new Era on the trasnport Control Protocol (TCP). Google announced integration with Google Cloud, a cloud hosting platform offered by Google to thousands of companies and which serves millions of websites on a daily basis.

BBR stands for “Bottleneck Bandwidth and RTT (Round-Trip Time),” and is an algorithm for optimizing how network packets travel through servers in order to avoid jamming certain routes.

If you want test this on your linux box, you can follow this guide here

An draft IETF proposal as been made, you check see it here

Some DNS Resources Compiled

Working a lot around Response Policy Zone (RPZ) these days, it’s better to start collecting some valuable tools, whitepapers, research, best practises, etc

DNS Servers

Name Description
BIND The most widely used DNS software on the Internet
Bundy Integrated authoritative DNS and DHCP server (the continuation of the BIND 10)
Dnsmasq A lightweight, easy to configure DNS forwarder and DHCP server
Knot DNS Knot DNS is a high-performance authoritative-only DNS server
PowerDNS A versatile nameserver which supports a large number of backends

Upgrade Cisco Blade Switch

Applying a major upgrade between 12.x and 15.x code, backup your config first before go ahead!

Checking the actual version


SW01#sh ver | i IOS
Cisco IOS Software, CBS30X0 Software (CBS30X0-LANBASEK9-M), Version 12.2(35)SE, RELEASE SOFTWARE (fc2)SW01#show boot
BOOT path-list      : flash:cbs30x0-lanbase-mz.122-35.SE/cbs30x0-lanbase-mz.122-35.SE.bin
Config file         : flash:/config.text
Private Config file : flash:/private-config.text
Enable Break        : no
Manual Boot         : no
HELPER path-list    :
Auto upgrade        : yes
Auto upgrade path   :

Downloading and extracting the TAR file from your TFTP

SW01#download-sw tftp:
Loading cbs30x0-ipbase-tar.150-2.SE6.tar from (via FastEthernet0): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(omitted for brevity)
[OK – 15073280 bytes]

Loading cbs30x0-ipbase-tar.150-2.SE6.tar from (via FastEthernet0): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(omitted for brevity)
examining image…
extracting info (107 bytes)
extracting cbs30x0-ipbase-mz.150-2.SE6/info (372 bytes)
extracting info (107 bytes)

Stacking Version Number: 1.49

System Type:             0x00000000
Ios Image File Size:   0x00BEF200
Total Image File Size: 0x00E60200
Minimum Dram required: 0x08000000
Image Suffix:          ipbase-150-2.SE6
Image Directory:       cbs30x0-ipbase-mz.150-2.SE6
Image Name:            cbs30x0-ipbase-mz.150-2.SE6.bin
Image Feature:         IP|LAYER_3|MIN_DRAM_MEG=128

Old image for switch 1: unknown

Extracting images from archive into flash…
cbs30x0-ipbase-mz.150-2.SE6/ (directory)
extracting cbs30x0-ipbase-mz.150-2.SE6/info (372 bytes)
cbs30x0-ipbase-mz.150-2.SE6/html/ (directory)
extracting cbs30x0-ipbase-mz.150-2.SE6/html/frmwrkResource.htm (950 bytes)
extracting cbs30x0-ipbase-mz.150-2.SE6/html/menu.shtml (8324 bytes)
extracting cbs30x0-ipbase-mz.150-2.SE6/html/portstats.js (8142 bytes)
(omitted for brevity)
extracting cbs30x0-ipbase-mz.150-2.SE6/cbs30x0-ipbase-mz.150-2.SE6.bin (12505683 bytes)
extracting info (107 bytes)

Installing (renaming): `flash:update/cbs30x0-ipbase-mz.150-2.SE6′ ->
New software image installed in flash:cbs30x0-ipbase-mz.150-2.SE6

All software images installed.

Boot updated with the new image & Reboot

SW01#show boot
BOOT path-list      : flash:cbs30x0-ipbase-mz.150-2.SE6/cbs30x0-ipbase-mz.150-2.SE6.bin
Config file         : flash:/config.text
Private Config file : flash:/private-config.text
Enable Break        : no
Manual Boot         : no
HELPER path-list    :
Auto upgrade        : yes
Auto upgrade path   :SW01#reload
Proceed with reload? [confirm]

New code is Live!

SW01#sh ver | i IOS
Cisco IOS Software, CBS30X0 Software (CBS30X0-IPBASE-M), Version 15.0(2)SE6, RELEASE SOFTWARE (fc2)

Compare the running config with the Backup one we did previously zero differences, so another successful upgrade!

Export/Import Putty settings

This method is using registry, so before proceed do a backup of it.

Open command line and type the following command:

regedit /e “%userprofile%\desktop\putty-registry.reg” HKEY_CURRENT_USER\Software\Simontatham

Copy the file generated to the new Windows installation and run it, a prompt window will pop up and click “Yes”. This will merge with config you have for Putty.


The following window should appear saying it was imported successfully.



Setup Infoblox IPAM Express on ESXi

You are running out of budget this moment but you really need an IPAM system to manage your IPs (IPv4 and v6) and leave away the old excel which you worked for a long time. For me using or not an IPAM system will depend of the environment size, it’s need to be reasonable and rational.

This free version supports 2000 hosts and multi-discovery, so not bad for a free product

The requirements to run this version from Infoblox are low (1vcpu, 1GB memory, 50GB), and it’s supported in VMware Player, VMware Workstation or VMware Fusion

I’ve tried convert strait away to vSphere 6 but didn’t work, so i started my journey until get this working, and i did it.

First we need to download the free copy, unzipped and use vCenter Converter to convert the image to our environment and play it.

Virtual Machine Properties

These are properties i used to setup my IPAM Express




Since IPAM Express doesn’t support a fixed IP, you need get a DHCP working for that subnet


After register you will receive an email like one below, open a browser https://ip-ipam and use credentials and download code provided


Importing Subnets and Hosts using a CSV file

To import a CSV you will need to respect a strict field format, you can use just a file for subnets and hosts, but i found it insane sometimes. For that reason i imported using different files.

File content subnets.csv


File content hosts.csv


Click on CSV Import on your left


Click on + signal


Select a CSV file to import, you can also use Options to control what you want to change. Press Start :)


After a successful import, you will see occupation of each subnet


Click on a subnet, you can show hosts using an IP Map or List



Drop me a comment if you need my ova file

Junos Genius 2.0 is out

Juniper redesign the interface of Junos Genius, and looks great.  There are other features included on this version: user profiles, fetch test exam questions, Sync Offline Data and much more
I really recommend it to practise before jump to a live exam, and it’s free!

Download the app now in the Apple AppStore or Google Play:


 junos_genius1  junos_genius2
junos_genius3 junos_genius4



Juniper Junos Genius

Dell FTOS Emulator

If you are a Dell Customer or Network Engineer who work with Dell gear, this is for you. Dell provide a Dell Networking OS Emulator for tests purpose, and gain experience with FTOS testing a few scenarios, there are a few limitations but still a good tool anyway. The best thing you can run it in VirtualBox which means you can easily integrate it with GNS3.
This emulator is based on 9.8 code, it is available for download here or get it directly from community:
Dell Emulator
User Guide

Supported Features

The Dell Networking Emulator supports the following features:
• Up to five data ports and one management port (five 40G or 10G ports)
• All management-related protocols and features such as simple network management protocol
(SNMP), telnet, secure shell (SSH)
• Layer 1 link up/down status when connected to another Dell Networking OS instance
• Optics emulation
• Layer 3 features such as routing and forwarding
• Routing protocols such as border gateway protocol (BGP), open shortest path first (OSPF),
intermediate system to intermediate system (ISIS), and routing information protocol (RIP)
• Management functionalities such as dynamic host configuration protocol (DHCP), Smartscripts,
authentication, authorization, and accounting (AAA), remote authentication dial-in user service
(RADIUS), terminal access controller access control system (TACACS+), management plane isolation
• Flash and nonvolatile random access memory (NVRAM)
• 40G and 10G interfaces
• Limited Layer 2 functionality such as LLDP, LACP

Unsupported Features

The Dell Networking Emulator does not support the following features:
• Most Layer 2 features
• Network boot
• Fast path
• Stacking
• virtual link trunking (VLT)
• Fast path features such as quality of service (QoS), buffer carving, Layer 2 virtual local area networks

Minimum System Requirements

The Dell Networking Emulator Requires the following:
• Any X86-based PC
• Microsoft Windows 7 operating system
• 16GB hard disk space for installing the ISO file
• A minimum of 512MB RAM per virtual machine instance
• Oracle VirtualBox, VMware, or Qemu.

Diagram below is in user guide which provides a small network with OSPF