Ahoy, Monks .. Here is some working code that I'd like to make better/more efficient. It has to do with decoding DNS and Netbios names in captured packets (pcap). I freely admit that the current method uses brute-force and inefficient methods. If someone has done something in this arena, please enlighten. tia . 

sub Decode_DNS_Name(){
    #DNS/Netbios Name decoder
    # This homegrown crazy bit of code developed by packet observation
+ only.
    my $nameref = shift;
    my ($retval, $namelen, $b1, $b2, $lastchar);

    $namelen = ord(substr($$nameref,0,1));
    for (my $i=1; $i <= $namelen; $i+=2){
       $b1=(ord(substr($$nameref,$i,1))) - 0x41;   #Don't ask me why .
+.
       $b2=(ord(substr($$nameref,$i+1,1))) - 0x41; # It just works thi
+s way!!
       $retval .= chr( ($b1 << 4)+$b2);
    }
    # Last byte of NB name is the "Type". chop it if it is ..
    if (($lastchar = chop($retval)) gt ' '){
      # Ooops ... That was a real part of the name ..Need to restore i
+t..
      $retval .= $lastchar;
    };
    #Trim trailing blanks
    $retval =~s/\s*$//;
    return $retval ; #.
}

[download]
Yes - I know - I should post sample Input and output strings .. Will get to that soon.

In reply to Parsing Netbios and DNS Names by NetWallah

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