At work we have a lot of Lucent ISDN Routers to configure, they come with a Java config utility, but this does not do everything we want, and besides I would like to automate the process down to a single script.

When an ISDN router is unboxed, it has no ip based settings at all. To avoid having to connect a serial cable to the device and give it an ip address, the Java config utility sends a UDP broadcast (255.255.255.255) to port 9 (discard) with the required ip settings in the data portion.

I have sniffed the traffic and successfully written a program to send the required UDP packet to 255.255.255.255. The ISDN router then replies with a confirmation packet, here lies the problem....
I can see the packet being transmitted from the ISDN router back to the pc doing the configuration, but I cannot get the perl program to receive that packet !
Does anyone have any source code to first send a broadcast then receive reponses from the hosts that send packets back ?

For reference the conversation normally goes thus:

PC: sends udp port 9, src: 192.168.1.1 dst: 255.255.255.255

ISDN: send udp response, src: <anything> dst: 192.168.1.1

Any help would be much appreciated !

In reply to UDP Broadcasts by jamesdmorris

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.