Debian/Ubuntu Tips and Tricks

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Debian/Ubuntu Tips and Tricks

Vmware Workstation: DNS not working with NAT

Posted by chantra on April 8th, 2009

Lately, I have been experiencing a funny network issue when using VMware Workstation VMs with NAT interface. Roughly, the IP network was working fine, but DNS resolution was not anymore. It happened intermittently, but I could see that this mainly happened when I was suspending my laptop, going to another location and resuming.

Forcing the VM to use a public DNS would solve the issue.

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Posted in HowTo, Softwares, Virtualization | No Comments »

How-to: Autotune/ Pitch Correction Effect with Praat

Posted by chantra on April 4th, 2009

I have been looking around for a while for an autotune effect (pitch correction, or whatever name you care to call it) for linux. Unfortunately everything I have found either cost money or wasn't for linux, or required special setup (wine, or other nasty things). All I could find in terms of linux autotune was people also looking for autotune. However, all the answers were unsatisfactory, either because they required manual pitch recognition (Not so good for the tone-deaf among us), or people confused it with pitch shifting in general. I eventually did find that praat (it's in synaptic), a speech analysis tool, comes surprisingly close to autotune functionality. It will give you a T-pain like effect, but it requires you to manually place the notes (although it will detect the pitch for you). I am not very experienced with praat, although this is what I figured out how to do (some of it from the original mailing list post, other I read from the manual or figured out).

Although it's GUI isn't too nice, and it isn't designed for musical manipulation, it gets the job done.
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How-To: Virtual emails accounts with Postfix and Dovecot — page 3

Posted by chantra on January 18th, 2009

5. Configuring Dovecot

Dovecot has its SQL configuration gathered in a separated file: /etc/dovecot/dovecot-sql.conf, so let's edit edit with our settings:

# vi /etc/dovecot/dovecot-sql.conf

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How-To: Virtual emails accounts with Postfix and Dovecot — page 2

Posted by chantra on January 18th, 2009

4. Configuring Postfix

4.1. main.cf and master.cf

Your postfix main.cf file should look like:

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How-To: Virtual emails accounts with Postfix and Dovecot

Posted by chantra on January 18th, 2009

This tutorial will explain how to run a mail server with virtual domains and users using a MySQL backend to store email informations.
Postfix will be our SMTP server, Dovecot will be handling IMAP (optionally one could configure POP3 also) so that users can retrieve their email.

Another tutorial will cover SPAM fighting using DSPAM based on this implementation (yet to be done).

This tutorial was done on Debian Etch using postfix 2.3.8-2etch4 and 1.0.rc15-2etch4.

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Posted in Administration, HowTo, Networking | 2 Comments »

How-To: Apache2 authentication using MySQL backend — page 2

Posted by chantra on December 17th, 2008

3. Creating users

Here we will be using sha1 password. To create a password, you can use the following command:

# echo -n 'password' | sha1sum
5baa61e4c9b93f3f0682250b6cf8331b7ee68fd8 -

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Posted in Administration, HowTo, HTTP, Networking, System | 5 Comments »

How-To: Apache2 authentication using MySQL backend

Posted by chantra on December 17th, 2008

this tutorial will explain how to use a MySQL backend in order to authentication users against your Apache website.

To achieve this we will use Apache2 and its auth_mysql module.

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Posted in Administration, HowTo, HTTP, Networking, System | 1 Comment »

How-To: Redirecting network traffic to a new IP using IPtables

Posted by chantra on December 6th, 2008

While doing a server migration, it happens that some traffic still go to the old machine because the DNS servers are not yet synced or simply because some people are using the IP address instead of the domain name....

By using iptables and its masquerade feature, it is possible to forward all traffic to the old server to the new IP.

This tutorial will show which command lines are required to make this possible.

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Posted in Administration, HowTo, Networking | 13 Comments »

How-To: Setting up BGP on Vyatta — page 3 — Setting BGP

Posted by chantra on November 2nd, 2008

3. Setting BGP

As told earlier on, vyatta-bgp1 will advertise AS 1 with network 1.1.1.0/24 to its neighbor vyatta-bgp2 handling AS 2
and
vyatta-bgp2 will advertise AS 2 with network 2.2.2.0/24 to its neighbor vyatta-bgp1 handling AS 1

They will use a common password for this communication, which is BGPtutorial.

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How-To: Setting up BGP on Vyatta — page 2 — Network interfaces

Posted by chantra on November 1st, 2008

2. Setting the network interfaces

During this part, we are going to set up the 2 Border Gateway routers'network interfaces. In vyatta world, you need to enter the interactive configuration shell by typing:

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