In my previous blog post you know how to make JunOS vdi to install into Virtuabox. Some of you may try to run it fromVBox main window. When ever you try to run JunOS from VBox window you may encounter below error message and nothing happen.

BTX loader 1.00 BTX loader is 1.02

Don't run it form the VirtuaBox main windows. Please go to my previous blog post.

Most of the time we may encounter following error. Such a error may occur if remote host may change or regenerated the RSA key. So how to solved the issue.

jpudasaini@Gnome:~/Downloads$ ssh root@10.0.2.37
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
f3:30:b1:66:ea:0d:e4:06:2e:10:8b:ca:df:33:fa:34.
Please contact your system administrator.
Add correct host key in /home/jpudasaini/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /home/jpudasaini/.ssh/known_hosts:17
  remove with: ssh-keygen -f "/home/jpudasaini/.ssh/known_hosts" -R 10.0.2.37
ECDSA host key for 10.0.2.37 has changed and you have requested strict checking.
Host key verification failed.

This error will happen due to the remote host change the host key.
ssh-keygen -R 10.0.2.37

jpudasaini@Gnome:~$ cd /home/jpudasaini/.ssh/
jpudasaini@Gnome:~/.ssh$ ls
known_hosts  known_hosts.old
jpudasaini@Gnome:~/.ssh$ sudo vi known_hosts
[sudo] password for jpudasaini:  (type your password)

Delete line 17 form opened file or

jpudasaini@Gnome:~$sed -i 17d ~/ssh/known_hosts

This will delete line 17 in the /ssh/known_hosts file

Now you retry to login to the remote host. Accept new key and ready to go.

 This is the Step 2 in our GNS3 Lab with JunOS, Quagga and Cisco router.

I have tried different tutorial posted in other blogs. I've never found any tutorial  work until now. Every-time I stuck at the middle of the tutorials.  In this blog post, I'll show you how to install JunOS in VBox and later I'll integrate it into GNS3 lab.

I have take Olive12.1R1.9.img, I know you're smart to get it from the Internet. Lets begin the installation of JunOS. Before that, convert the JunOS image into Vbox vdi Image.

For easy installation and to avoid error during this tutorial, enter into the JunOS folder, in my case.

This tutorials assume that you have already install GNS3 and VBox.


Step 1

Prepare JunOS for VBox.

C:\Users\jpudasaini\Desktop\jun>"C:\Program Files\Oracle\VirtualBox\VBoxmanage" convertdd Olive12.1R1.9.img Olive12.1.R1.9.vdi

Its take time to convert the image, wait for few minute depends on your PC configuration.

Now go to the jun folder you can see Olive12.1R1.9.vdi image is created.

Step 2

• Open VBox and create New Virtual Machine and give any name choose BSD then FreeBSD.
• On next window choose at least 512MB RAM, click next.
• Now its important step, while choosing Hard Drive in this step select "Use an existing virtual hard drive file". Then locate previous created vdi file. In my case "c:\user\jpudasaini\Desktop\jun\Olive12.1R1.9.vdi"
• Its time to open GNS3>Edit>Preferences>VirtualBox>VirtualBox Guest

1. Identifier name: Juniper
2. VM List:- JunOS(In this step you may not seen any VBox OS just click "Refresh VM List"
3. Click "save" and go the GNS3 main window, 

Add VirtualBox Guest in GNS3 working area. Becareful in this step, don't run guest OS from VBox, just run it from GNS3 Working enviroment area, right clicking and start.

• To login to router console just right click JunOS and choose"console" now you can login to router console with ID "root" no password.

Often I've forgotten Ubuntu password, this is the most occurring issue with me. Every-time I have to search Google how to reset the password on Ubuntu. So I decide to make notes for myself.

Here is the step how I reset the password.

First of all reboot Ubuntu and choose recovery mode from console. After that you may see "Recovery menu", just choose "root Drop to root shell prompt".

Now you are in a shell prompt, then use following command to change the password.


 #ls /home (this will show your home directory's username)
#mount -rw -o remount /
#passwd (username)
Enter new UNIX password:
Retype new UNIX password:
passwd Password updated successfully
#reboot

After wards you can use new password to login to ubuntu. Tested in Ubuntu server 14.04.

Here is the procedure how to run your Cisco Router as DHCP server.
******output omitted ********

!
!
!
!
ip dhcp excluded-address 192.168.10.1
!
ip dhcp pool test
 network 192.168.10.0 255.255.255.0
 default-router 192.168.10.1
 dns-server 8.8.8.8
!
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.10.1 255.255.255.0

On your outlook express while sending the emails and you get following error.

Cannot send the message. Verify the e-mail address in your account properties. The server responded: 550 Access denied - Invalid HELO name (See RFC2821 4.1.1.1)

1. Click Tools>Account
2. Select"View or change existing e-mail accounts" and click next
3. Select desire email account and click change
4. Click on "More Settings" at bottom of the page
5. Select on "Outgoing server" tab
6. Check "My outgoing server (SMTP) requires Authentication"
7. Select "use same settings as my incoming email server"
8. Click "Ok"
9. Press Next and Finished 

I have to day to day network troubleshoot and I need such a tool which shows what program consume the network bandwidth. So the Nethogs tool is small net top tool which fit exactly under my requirements. Here is the process to install and use of the tool.


The tool monitors traffic going to and from a machine, by per process basis.

jpudasaini@jpudasaini:~$ sudo apt-get install nethogs
 
*****Output*******

[sudo] password for jpudasaini:
Reading package lists... Done
Building dependency tree      
Reading state information... Done
The following packages were automatically installed and are no longer required:
  kde-l10n-engb linux-image-generic
Use 'apt-get autoremove' to remove them.
The following NEW packages will be installed:
  nethogs
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 28.3 kB of archives.
After this operation, 105 kB of additional disk space will be used.
Get:1 http://np.archive.ubuntu.com/ubuntu/ saucy/universe nethogs amd64 0.8.0-1 [28.3 kB]
Fetched 28.3 kB in 0s (50.1 kB/s) 
Selecting previously unselected package nethogs.
(Reading database ... 230384 files and directories currently installed.)
Unpacking nethogs (from .../nethogs_0.8.0-1_amd64.deb) ...
Processing triggers for man-db ...
Setting up nethogs (0.8.0-1) ...

You have install the tool. How to use the tool.

#sudo nethogs
#sudo nethogs eth0