And yet another way. You can capture an incoming connection via tcpdump and write it to file. Then use can use Net::TcpDumpLog to read the tcpdumplog. It'll return some raw packet data in Ethernet/IP/TCP form usually. I took the two examples provided by Brenden Gregg and put them together. If you don't have a tcpdumplog, then use the one provided in the source.

You will need to put this script and the tcpdumplog in the same directory for it to work. 

#!/usr/bin/perl
#
# example01.pl - Example of Net::TcpDumpLog. Prints out frame arrival 
+times.
#
# 11-Oct-2003    Brendan Gregg    Created this

use Net::TcpDumpLog;

$log = Net::TcpDumpLog->new(32);    
$log->read("tcpdumplog");        
                
$count = $log->maxindex + 1;
@Indexes = $log->indexes;

print "Log version : ",$log->version,"\n";
print "Linktype    : ",$log->linktype,"\n";
print "Packet count: $count\n\n";

printf "%5s  %25s  %7s %5s  %s\n","Frame","Arrival time","+ MSecs","Dr
+ops",
 "Length";

foreach $index (@Indexes) {
    ($length_orig,$length_incl,$drops,$secs,$msecs) = $log->header($in
+dex);
    $data = $log->data($index);

        $time = localtime($secs);

    $msecs = $msecs / 1000000;
    $length = length($data);

    printf "%5d  %25s  %7.5f %5d  %d\n",$index,$time,$msecs,$drops,$le
+ngth;
}

# example02.pl - Example of Net::TcpDumpLog. Prints out ethernet heade
+rs.
# 11-Oct-2003    Brendan Gregg    Created this

$log->read("tcpdumplog");        
                    
@Indexes = $log->indexes;

printf "%5s  %12s    %12s  %4s  %s\n","Frame","Source","Dest","Type","
+Length";

foreach $index (@Indexes) {
    $data = $log->data($index);

    ### Process Ethernet header
    ($ether_dest,$ether_src,$ether_type,$ether_data) = 
     unpack('H12H12H4a*',$data);
    $length = length($ether_data);

    printf "%5d  %12s -> %12s  %4s  %s\n",$index,$ether_src,$ether_des
+t,
     $ether_type,$length;

}

[download]

In reply to Re: explore tcp/ip stack by Khen1950fx
in thread explore tcp/ip stack by sveni

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.