Adi Linden

  • Using Cisco IP Phones with Asterisk

    Oct 10, 2005 • Comments

    My home telephone system is a Asterisk Open Source PBX. The actual handsets are Cisco IP phones. In this document I am describing the steps taken to setup the TFTP files needed to provision and manage Cisco phones.

    Filed under: Sysadmin • Tags: asterisk, cisco
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  • My Debian GNU/Linux (Sarge Release) Mail Server

    Oct 9, 2005 • Comments

    These instructions describe the installation of a Debian GNU/Linux based mail server. The server is a closed system, without user shell accounts. Mail accounts are administered using web based tools. This provides for excellent system security.

    Filed under: Sysadmin • Tags:
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  • Image Popup Javascript

    Feb 20, 2005 • 0 Comments (disabled)

    I know that popup windows are being frowned upon at most times. However, I personally like the use of a popup window to obtain the larger version of an image thumbnail on a page. I make liberal use use of this on my web pages. One of my attempts of a popup image window is described here.

    Filed under: Coding • Tags: java, programming
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  • IRLP Now

    Feb 15, 2005 • Comments
    This article describes the construction of the VA3SLT repeater. The repeater is full-duplex and operates on 147.315 MHz transmit and 147.915 MHz receive. A tone of 127.3 Hz is required to access the repeater.
    Filed under: Amateur Radio • Tags: amateurradio, electronics, irlp
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  • Redirect HTTP Requests

    Oct 18, 2004 • 0 Comments (disabled)

    Here is a small perl script I wrote to redirect http requests from one server to another. Intead of running web server software, such as apache, this little script is invoked by inetd. The inetd daemon is configured to listen to port 80 and any incoming connection to port at is passed to this script to be handled. I make no claims that this is secure or reasonable thing to do.

        #!/usr/bin/perl
    #
    # /usr/local/bin/http-redirect
    #
    # $Id: http-redirect,v 1.4 2004/10/18 23:55:46 adi Exp $
    # 
    # This perl script redirects browsers to another host/URL. It is meant to
    # be run from inetd or xinetd.
    #
    # This is an example configuration for xinetd:
    #
    #    service http-redirect
    #    {
    #        type                = UNLISTED
    #        socket_type         = stream
    #        protocol            = tcp
    #        wait                = no
    #        user                = nobody
    #        server              = /usr/local/bin/http-redirect
    #        port                = 80
    #        disable             = no
    #    }
    #
    # This is an example line for inetd
    #
    #    http stream tcp nowait nobody /usr/local/bin/http-redirect 
    #
    
    use POSIX;
    
    #
    # This subroutine returns time and date in rfc822 format. It wous found
    # at <http://www.tbray.org/ongoing/When/200x/2003/03/15/PerlGrind>.
    #
    sub rfc822
    {
        my $t = shift;
        $t = time unless $t;
        my $rfc822 = "%a, %d %b %G %T %Z";
        return POSIX::strftime($rfc822, localtime($t));
    }
    
    #
    # Define the parts of the message
    #
    $date = rfc822;
    $code = '302 Redirect';
    $url  = 'http://webmail.example.com/';
    
    $mbody = <<EOM;
    <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
    <HTML><HEAD>
    <TITLE>$code</TITLE>
    </HEAD><BODY>
    <H1>$code</H1>
    <P>This server has no documents.
    <P>Goto <a href="$url">$url</a> instead.
    </BODY></HTML>
    EOM
    
    $mlength = length($mbody);
    
    $mheader = <<EOM;
    HTTP/1.1 $code
    Date: $date
    Server: http-redirect/0.1
    Location: $url
    Content-Type: text/html
    Content-Length: $mlength
    EOM
    
    # Assemble message and make line termination CR+LF
    $message =  $mheader . "n" . $mbody;
    $message =~ s/n/rn/gm;
    
    # Read the input, actually we're just looking for a blank line
    while (<>) {
        last if (/^s*$/);
    }
    
    # Send output
    print $message;
    exit;
    Filed under: Coding • Tags:
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  • UoSAT-Oscar-11

    Mar 3, 2004 • 0 Comments (disabled)
    My first QSL card! OSCAR-11. This bird has been in space for 20 years.
    Filed under: Amateur Radio • Tags: amateurradio
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