if ( @ips = $line =~ /[\d.]{7,15}/g ) {
    $client_ip{$ips[0]}{$iteration}++;
    . . .
}
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If you need to check the validity of the line, you can wrap that in something like (using the regex from Mastering Reg Exps as cited here):

$numrx = qr/[01]?\d\d?|2[0-4]\d|25[0-5]/;
$iprx = qr/($numrx\.){3}$numrx/;
if ( $line =~ /^(\s*($iprx):\d+\s*->){2}\s*$iprx/ ) {
   . . .
}
[download]

Or, of course combine them: if ( $line =~ /^\s*($iprx):\d+\s*->\s*($iprx):\d+\s*->\s*($iprx)/ ) {
  p