Sunday, March 6, 2011

Single Interface Squid Proxy Server

This is a brief introduction to Squid proxy that covers Setting up Squid on Ubuntu/Debian with a single network card, and routing traffic through it. I use this for testing websites remotely before putting them live, but it would also be possible to setup a similar box to monitor network traffic.
Before you begin you should have a computer setup with Ubuntu/Debian. I am using Ubuntu 10.04 LTS for my proxy. The rest of these instructions will assume that this is installed and configured on your network as you want it. Also note that Debian users should su to root instead of typing sudo.
1. Get squid
First thing’s first, we need to get squid. This can be achieved by typing the following into  the terminal:
sudo apt-get install squid
This will download squid from the repositories and set it up on your machine.
2. Setup Squid
This is easy if you know what you’re doing. The squid config file is in the /etc/squid/ directory, so open it up in a text editor:
sudo nano /etc/squid/squid.conf
Now we need to add the lines to allow access to your network. If you’re in nano you can use
Ctrl+w and type acl all src all
Since I’m setting this up as a remote server I have to allow my IP address for work to be able to access the proxy. Here’s the lines I added:
acl remotenet src 123.123.123.123 #Work’s external IP address
further down the script there’s a line that reads http_access allow localnet, under this line add:
http_access allow remotenet #allow connections to this proxy server from “remotenet”
Understanding this process
ACL is an access control list, which you’re assigning IP addresses to. in the above two lines you’ve allowed the IP address 123.123.123.123 access to the proxy server. You can continue adding IP addresses to the remotenet group my copying and pasting the first line you entered but with different IP addresses.
At the end to the file you’ll also need to add the following line of code:
visible_hostname someProxyServerName
Exit and save the squid.conf file by pressing Ctrl+x and pressing Y when asked if you want to save changes, followed by enter to overwrite the file.
restart squid: sudo service squid restart
3. Setting  Up Your Web Browser
You should now be able to access your server by setting the proxy details up in your browser as the following:
Proxy: your squid IP address/DNS name
Port: 3128

courtesy of SIRNET

Squid Analysis Report Generator (SARG) and Webmin

The Squid Analysis Report Generator (SARG) enables you to see your Squid users internet usage. SARG provides many informations about Squid users activities like times, bytes, sites, etc. This article will show you how to use SARG through Webmin, a web-based interface for administering Linux.


Installing Webmin and SARG

RPM Forge 
1. Add the RPMforge repository into Yum. We will be getting the SARG RPM package for Red Hat/CentOS from RPMforge.
Yum install SARG 
2. From a terminal window, type in the command below to install SARG.
yum install sarg
Webmin 
3. Install Webmin. After installing, login to Webmin. Webmin will enable us to control who gets access to the Squid reports. We will also have an easy to use web-based interface for configuring the report format.
SARG configure 
4. Click Un-used modules in the side bar. Next click Squid Report Generator. We need to configure SARG so click module configuration.
SARG configure 
5. Change the value of Full path to SARG configuration file to /etc/sarg/sarg.conf then click the Save.
NoteNext time you need to use the Squid Report Generator, look for it under Servers instead of Un-used modules.

Generating a report

SARG 
1. To generate a report, click the Generate Report Now button.
SARG 
2. Next, click View completed report.
SARG 
3. Click the latest generated report.
SARG 
4. Review the generated report.

Sunday, February 13, 2011

Online Diagram Software and Flowchart Software - Gliffy

Online Diagram Software and Flowchart Software - Gliffy
Need a replacement for your Visio software? Here's an online application where everything you need for illustrations, visualization and diagramming capabilities can be found from a single site.
It's a cloud application...
Well apparently, I just used some proprietary application such as Visio2007 when I'm using a Windows platform. But since most of the time I use Linux, I tend to use Dia which is also a good free application but not that as graphically smooth like Visio. Anyway, it doesn't really matter how it looks because my main purpose is to have a diagram for my analytical info and design. And until I found Gliffy which is I think its been there for quite sometime.

I made a sample layout for my trial period.

Sunday, January 9, 2011

Convert AVI to MP4 in Fedora 14 Linux

The Mplayer program includes a utility for converting multimedia from one format to another called MEncoder. The MEncoder utility can be used to convert AVI video files to the MP4 format from the command line. The resulting video can be played on Apple iPods and other handheld devices. The MP4 format is based on the Apple Quicktime container format. MP4 can contain audio only, or audio and video together. However, the standard is to use MP4 to refer to video files and M4A to refer to audio only files.
Difficulty: Easy

Instructions

Things You'll Need:

* MPlayer, MEncoder

1.Download and install MPlayer through your distribution's software repository, or from the MPlayer website.
2.Open a terminal window.
3.Type the command "mencoder input.avi -o output.mp4 -oac copy -ovc lavc -lavcopts vcodec=mpeg1video -of mpeg" to convert the AVI video to MP4.
4.Type the command "mplayer output.mp4" to test the video.
5.Type the command "exit" to close the terminal session.


If you dant have Mplayer installed, just type in terminal
# yum install mplayer mencoder

(must be root to install)

Saturday, January 8, 2011

Old schematics from my 10 year old backup

I have here some of my old schematic diagrams which I compiled around 10 years ago. I have decided to post here as another copy from my angelfire.com account  but in no particular order/details.

For those electronic enthusiast, you may find below classic diagrams useful on some of homebrew projects and repairs.


200W PC ATX Power Supply

35Amps, 13.8VDC Regulated Power Supply for HAM/Amateur Radio Enthusiast

Hi-Power Amplifier - Diect-Coupled railing output

Thursday, December 30, 2010

'Data Cap' - NTC's proposed data caps violate consumer rights, lawyer says

I've been a 3G broadband user since 2007, and now such policy has to be materialized in-order to serve millions of user wirelessly.

If you observe those Blackberry users are kinda tech savvy fond of twitting and posting stats on FB and same with iPhone users, Smartphones has began since around +5 years ago and yet the real bandwidth which is capable of, can only be experienced smoothly right now.

Imagine how many users on mobile passing to all that microwave repeaters/cellsites with different comm-features (text, calls & internet) if without certain restrictions, real heavy net traffic can be experienced.

Although, in near future, much larger data bandwidth can be serve to us like HSPA, HSUPA & 4G.





Thursday, November 18, 2010

Install Squirrel Mail on Ubuntu 10.04 server

To install the SquirrelMail webmail client, run

aptitude install squirrelmail

Then create the following symlink...

ln -s /usr/share/squirrelmail/ /var/www/webmail

... and configure SquirrelMail:

squirrelmail-configure

We must tell SquirrelMail that we are using Courier-IMAP/-POP3:

SquirrelMail Configuration : Read: config.php (1.4.0)
---------------------------------------------------------
Main Menu --
1. Organization Preferences
2. Server Settings
3. Folder Defaults
4. General Options
5. Themes
6. Address Books
7. Message of the Day (MOTD)
8. Plugins
9. Database
10. Languages

D. Set pre-defined settings for specific IMAP servers

C Turn color on
S Save data
Q Quit

Command >>
<-- D


SquirrelMail Configuration : Read: config.php
---------------------------------------------------------
While we have been building SquirrelMail, we have discovered some
preferences that work better with some servers that don't work so
well with others. If you select your IMAP server, this option will
set some pre-defined settings for that server.

Please note that you will still need to go through and make sure
everything is correct. This does not change everything. There are
only a few settings that this will change.

Please select your IMAP server:
bincimap = Binc IMAP server
courier = Courier IMAP server
cyrus = Cyrus IMAP server
dovecot = Dovecot Secure IMAP server
exchange = Microsoft Exchange IMAP server
hmailserver = hMailServer
macosx = Mac OS X Mailserver
mercury32 = Mercury/32
uw = University of Washington's IMAP server
gmail = IMAP access to Google mail (Gmail) accounts

quit = Do not change anything
Command >>
<-- courier


SquirrelMail Configuration : Read: config.php
---------------------------------------------------------
While we have been building SquirrelMail, we have discovered some
preferences that work better with some servers that don't work so
well with others. If you select your IMAP server, this option will
set some pre-defined settings for that server.

Please note that you will still need to go through and make sure
everything is correct. This does not change everything. There are
only a few settings that this will change.

Please select your IMAP server:
bincimap = Binc IMAP server
courier = Courier IMAP server
cyrus = Cyrus IMAP server
dovecot = Dovecot Secure IMAP server
exchange = Microsoft Exchange IMAP server
hmailserver = hMailServer
macosx = Mac OS X Mailserver
mercury32 = Mercury/32
uw = University of Washington's IMAP server

quit = Do not change anything
Command >> courier

imap_server_type = courier
default_folder_prefix = INBOX.
trash_folder = Trash
sent_folder = Sent
draft_folder = Drafts
show_prefix_option = false
default_sub_of_inbox = false
show_contain_subfolders_option = false
optional_delimiter = .
delete_folder = true

Press any key to continue...
<-- ENTER


SquirrelMail Configuration : Read: config.php (1.4.0)
---------------------------------------------------------
Main Menu --
1. Organization Preferences
2. Server Settings
3. Folder Defaults
4. General Options
5. Themes
6. Address Books
7. Message of the Day (MOTD)
8. Plugins
9. Database
10. Languages

D. Set pre-defined settings for specific IMAP servers

C Turn color on
S Save data
Q Quit

Command >>
<-- S


SquirrelMail Configuration : Read: config.php (1.4.0)
---------------------------------------------------------
Main Menu --
1. Organization Preferences
2. Server Settings
3. Folder Defaults
4. General Options
5. Themes
6. Address Books
7. Message of the Day (MOTD)
8. Plugins
9. Database
10. Languages

D. Set pre-defined settings for specific IMAP servers

C Turn color on
S Save data
Q Quit

Command >> S

Data saved in config.php
Press enter to continue...
<-- ENTER


SquirrelMail Configuration : Read: config.php (1.4.0)
---------------------------------------------------------
Main Menu --
1. Organization Preferences
2. Server Settings
3. Folder Defaults
4. General Options
5. Themes
6. Address Books
7. Message of the Day (MOTD)
8. Plugins
9. Database
10. Languages

D. Set pre-defined settings for specific IMAP servers

C Turn color on
S Save data
Q Quit

Command >>
<-- Q

Afterwards you can access SquirrelMail under http://server1.example.com/webmail or http://192.168.0.100/webmail:

Monday, November 15, 2010

How to add a user to the sudoers list

How to add a user to the sudoers list? Beleive it or not, this is a fairly common question and in all reality the answer is quite simple. Adding a user to the sudoers list on a fully installed Linux system such as Debian is only possible via the command visudo. Users in the sudoers list are allowed the privileges to run commands and open files as the root user. In the following quick tutorial, we will show you how adding a new sudoer is quickly done.

How to add a user to the sudoers list:

  1. Open a Root Terminal and type visudo (to access and edit the list)
  2. Using the up/down arrows, navigate to the bottom of the sudoers file that is now displayed in the terminal
  3. Just under the line that looks like the following:
  4. root ALL=(ALL) ALL

  5. Add the following (replacing user with your actual username):
  6. user ALL=(ALL) ALL

  7. Now press Ctrl+X and press Y when promted to save

That's it, your new user now has root privileges!

Example Sudoers Screenshot:

Adding a new sudoer

Saturday, November 6, 2010

My old server room

Back in 2004, this is my training grounds after my contract in Toshiba as ISG data center support. I am the MIS assistant of a multi-national company that has four branches located in different areas in Laguna. I was stationed on their logistics head quarters in laguna technopark.

My network hosts 3 branches, we are the 4th and act as main host provider to Binan, Cabuyao and Calamba factories; all branches interconnected via private leased line. We have ATM direct network from HK and VPN's serving VoIP phones between HK, UK and PH.

It was a very simple network consisting one primary domain controller (windows 2000 server), and four mail servers running POP3 iMAIL.

My main network head units consists of cisco routers/catalyst, HP/Compaq server, 3com and Cisco layer 3switches and few Nokia modems. Cisco configs is the hardest part when we started with the setups.

I have here a short video that was taken secretly before it goes for rehabilitation and shelve it in a ventilated cabinets.