Wednesday, August 26, 2009

Adding a persistent static route in Linux - RHEL

If you know there is always going to be a permanent route for a destination then a static route can be a viable option.To add a persistent static route in Redhat Enterprise Linux create a file called route-X in the /etc/sysconfig/network-scripts/ directory

where is the interface number and X is the interface number. As you would expect, these are specified in seperate file for each of the available interface.



Every entry or a route has three entities as follows:

As the names implies, they are the gateway IP, Netmask and the IP/Network Address

Note the next to each of the three entities. This number defines the route entry number and should be the same on all the entities.




A sample file /etc/sysconfig/static-routes is available for your reference.

Once the file is created, restart the network service as follows:

# service network restart

To view the routes type

# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface * U 0 0 0 eth0 * U 0 0 0 eth1 * U 0 0 0 eth0 * U 0 0 0 eth0 * U 0 0 0 eth1
default UG 0 0 0 eth0


# ip route show dev eth0 proto kernel scope link src dev eth1 proto kernel scope link src via dev eth0 via dev eth0
default via dev eth0

To dynamically add a route, try the folowing:

# ip route add / via dev X


# ip route add via dev eth0



# route add [-net|-host] netmask gw dev X


# route add -net netmask gw dev eth0

This should help.

Tuesday, August 18, 2009

Turn off System Beep in Windows XP

When you spend a lot of time in front of your computer, the annoying beeps start to drive you mad after a while. I really don’t need to be told that I hit the wrong key anymore, so I’ve compiled a list of how to turn off all the system beeps in Windows XP.

One of the most irritating beeps happens when you use the Volume control… but there are other beeps, such as on error dialogs or when you hit the wrong key.


Disable Beep in Device Manager

Open up Device Manager by right-clicking on Computer and choosing Properties, then on the Hardware tab you’ll find the button for Device Manager.


Select View \ Show hidden devices from the menu.


Find Non-Plug and Play Drivers in the list, and then right-click on “Beep” and disable it:


When it prompts you to reboot, select no, and then right-click again and choose Properties this time. On the Driver tab, change the Startup type to “Disabled” and then click the “Stop” button if you are able to.


This should disable the system beep speaker, but it probably won’t change the volume control beep, so continue on.

Disabling Beep in Registry

Open up regedit.exe through the run box, and then navigate down to the following key:

HKEY_CURRENT_USER\Control Panel\Sound


Find the “Beep” key on the right-hand side and change the value to “no”.

Disable Beep in Sounds Panel

Open up Control Panel and find the Sounds and Audio Devices panel, choose the Sounds tab and then find “Default Beep” in the list.


Change the sound drop-down on the bottom to “None” and then click Apply. This should disable the volume control beep.

You’ll want to also change Critical Stop to “None” as well, and should probably also turn off some of the other items.

You can also use TweakUI to get rid of some of the beeps, but if you follow the items on this page you shouldn’t need that.

Original Source:

Monday, August 17, 2009

Gtalk Scroll Bar

To see all your friends instead of just the one page default, Login to gtalk, at the bottom of the gtalk window you will see a button "View". Click on this button and unclick 'show in one page' (you will need to click that option), that’s it you will see a scrollbar.

Friday, August 14, 2009

Check all IMAP folder for new email on Thudnerbird

Thunderbird can download mail from all accounts when you start the program. Just open the Config Editor from Preferences --> Advanced --> Config Editor, search for the preference mail.check_all_imap_folders_for_new, and change its value to true.

Using Certs for Authentication with Putty

This guide is based on PuTTY and PuTTYgen release versions .58, and assumes some knowledge of SSH and working with files on the server and your computer.

PuTTYgen can be used to generate a key pair which will allow you to log in via SSH using public key authentication.

PuTTY and PuTTYgen can be downloaded from:

Let's get started.

Open PuTTYgen and under Parameters you should see the defaults of SSH-2 RSA and 1024 for number of bits in generated key. These settings are fine, and you can just leave them.

Generate key

Click the "Generate" button and a progress bar will appear. PuTTYgen will ask you to move the mouse around to "generate randomness"...just move the mouse around in the blank space using random motions while it processes...

When it's finished, you will need to enter some information for your key file. The key comment field is basically another way of saying "name" of the key file... It tells you which key file it is... The default "key comment" will be in the form of key type and date. If you have more than one key, you will probably want to name them accordingly to tell them apart. For example: mysite-rsa-key-20050504

Comment and Passphrase

Your key passphrase, if you choose to use one, is what you will have to type when connecting to the server (you can use Pageant to automatically do this for you...for a guide on Pageant, visit can also be downloaded from the location referenced above for PuTTY and PuTTYgen). If you do not wish to use a passphrase, then do not type a passphrase at this point and the key will be saved unencrypted. Not using a passphrase will allow you or anyone using the key file to automatically connect to your account, without requiring a passphrase to be entered when connecting. To set a passphrase, you'll need to type it and confirm it where asked. If you use a passphrase, just make sure that you DO NOT FORGET IT as you cannot recover it.

Next, you will need to save your private key file.

Save Private Key

Click "Save private key". The save box will come up and you'll need to select a directory on your computer to save it to and type in a filename for it (be sure to leave the file type as .ppk).

Now you'll need to upload the public key contents to your account on the server.

Public Key Contents

You can do this process using the CNC or via SSH using the Unix shell. Brief instructions for both follow.

Installing the public key using the CNC:
Navigate to your /big/dom/xDOMAIN/USERNAME (replace xDOMAIN with your xdomain and USERNAME with your account username) directory and create a directory within it named .ssh. Set the permissions on the .ssh directory to 700 (see How do I change file permissions? (chmod) if you need help with changing file permissions.)

Within the .ssh directory, create a file named authorized_keys. Copy the entire contents of the box where it says "Public key for pasting into OpenSSH authorized_keys file" (starting at ssh-rsa) and paste them into the authorized_keys file (be sure to copy it exactly as it is and include no leading or trailing spaces or line breaks). Set the permissions on this file to 600 (see How do I change file permissions? (chmod) if you need help with changing file permissions.)

Installing the public key from the Unix shell:
Log in to your account using SSH and while in the $HOME directory (/big/dom/xDOMAIN/USERNAME), do the following:
$ mkdir .ssh
$ echo "paste public key contents here" >> .ssh/authorized_keys
$ chmod 600 .ssh/authorized_keys
$ chmod 700 .ssh

Now that you have created your key files and installed your public key on the server, it's time to start up PuTTY.

In PuTTY, under Session, enter your Host Name - this is simply your domain name (no www or http) - ex:

Select SSH for the protocol. (You should now see 22 for the port.)

Under SSH, choose 2 from Preferred SSH Protocol Version. (shown below)

SSH2 Preferred

Under SSH -> Auth in PuTTY, you will need to specify where your private key can be found. Remember this is where you saved the private key on your local computer. Click Browse to locate the file on your computer. (It will be the file with the .ppk extension.)

Private Key Location

If you wish to have your username automatically sent to the server when connecting, under Connection -> Data in PuTTY, you will see a field for "Auto-login username". Type your account username there.

Account Username

Save your settings to be used in future sessions - Under Sessions, type a name (such as "my site") in the Saved Sessions box and click Save.

Save Session

Now, select that session name by clicking on it and click Open.

Open SSH

If you did not set PuTTY to automatically enter your username, you will need to do so when prompted. After the username has been given, if you used a passphrase when creating your key file, you should see a message that says something like:

Authenticating with public key "keyfilename"
Passphrase for key "keyfilename":

Enter your passphrase if prompted. You should now be successfully logged in.