here's my next attempt,

Actually, this is two attempts. After playing around with my original twist a couple of times, i found that to do what it needs to do it would have to be longer than your original code. So i instead took your original code and chopped off unimportant bits and did some reformatting. Both of the following snippets seem to test out correctly (using warnings and strict):

/^Received[^\[]+\[(\d+).(\d+).(\d+).(\d+)]/?`host $4.$3.
$2.$1.$ARGV[0] 2>&1`=~/$ARGV[1]/m&&exit 0:1while<STDIN>;
exit 1

while(<STDIN>){s/^Received[^\[]+//&&s/].*//?($_='host '
.(join'.',(reverse map{s/(\D+)//;$_}split/\./),$ARGV[0]
).' 2>&1',`$_`=~/$ARGV[1]/m&&exit 0):1}exit 1
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The first one is based off of yours, i'm sure there's a way to squeeze it further, but i can't see it from here. The second is a re-working of my previous answer, and is obviously inadequate space-wise.

Hope This Helps,
jynx

PS i'm not sure how space-conscientious you want to be, but you could also shorten the first line to:

eval join"",map{chop;s/^[^>]+>\s*//&&$_}<DATA>__END__
[download]

if you're really desperate for space. As always, it could probably be shortened more... :)