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Uncompressing Cisco .cop.sgn file

Cisco releases some files (firmware, language files, ...) as .cop.sgn files. And sometimes, you need to uncompress it and reach files in this archive. "sgn" means, it is signed. Actually, there is only authentication header, which can be removed by editor. For Linux, we can use Bless hex editor. Open file in editor, and find pattern '1F 8B 08'.

Your file should start with this pattern.

How to connect from remote location to a GNS3 router console

Remote telnet access from an remote IP address (PC, NB) to an console of router which is running on different PC/server is common practise used within dynagen/dynamips environment. However it works within GNS3 too. I was looking how to setup it, here is a short guide for system environment with GNS3 version 1.2.3 installed on my notebook running Win 7 Pro 64 bit.

Keeping PuTTY telnet session alive

Working with my HP Terminal server, which we are using as a remote console acccess solution allows us login into Cisco router console ports remotely, i'm loosing the Putty connection due to inactivity. However the PuTTY client can be configured to maintain a connection and not time it out. All what we need to do is setup built-in keepalive machanism:


1. Open the PuTTy application 

Upgrade FreeSWITCH from compiled to package 1.5.8


First, add repository to system

vim /etc/apt/sources.list

add line

deb http://files.freeswitch.org/repo/deb-master/debian/ wheezy main

Then add GPG key to repository

gpg --keyserver pool.sks-keyservers.net --recv-key D76EDC7725E010CF
gpg -a --export D76EDC7725E010CF | apt-key add -

Now, update repository

apt-get update

FreeSWITCH is ready to install. Just run

How to setup auto start for virtual machines within XenServer 6.2

For XenServer of versions 6.x were removed direct GUI ability to setup auto-start of Virtual Machines after the startup of main XenServer server. This ability have to be setup using CLI (Command line). To do that we have to:

1) Use ssh client for login into your xen server, and become the root

2) List your VM machines using the command:

 xe vm-list

in my case the command provides the list of my machines. From the list we mainly need the UUID identity of VM:

Finding forgotten MikroTIK password using MKBrutus (on Kali Linux)

Upgrade Siremis 3.2.0 to 4.1.0

Download Siremis 4.1.0

Go to your desired folder (for example /var/www) and download Siremis from site http://siremis.asipto.com/pub/downloads/siremis/.

cd /var/www/
wget http://siremis.asipto.com/pub/downloads/siremis/siremis-4.1.0.tgz

Then extract Siremis folder from archive

tar -xvf siremis-4.1.0.tgz

Folder siremis-4.1.0 appears here.


Making a qemu MikroTik router for GNS3 under Win7

Resizing a VirtualBox Linux VDI Disk under Windows Host - VBoxManage error - Resize hard disk operation for this format is not implemented yet!

Using my VirtualBox linux machines (KaliLinux in my case) together with applying a couple of updates brought a problem, where the VB machine starts run out of disk space and I'm not able to update neither extend the system. This could be an often problem once we are trying to save some host system hard disk space using a small initial size of virtual machine disk partitions (12GB here).

The disk file cmd (df) reports:

CCNP - Route redistribution - Simulating routing loops


Teaching CCNP ROUTE courses and describing the problematic of two-way routing redistribution I need an example describing the case which point out to the process of creating a routing loop. This example shows how such routing loop may arise using badly configured redistribution process andusing bad seed metric. The topology with two redisitributing routers creates routing feedback (two way, multipoint redistribution). The loop is created for packets routed from the ospf network to the destination network.

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