Ok, so it looks like your nudge nudged me enough. The loop now looks like this:

for my $line(
            map  { $_->[2] }
            sort {
                     $a->[0] cmp $b->[0]
                             ||
                     $a->[1] <=> $b->[1]
            }
            map  {
                    my @vals = split /\s/, $_;
                    my( $sourceserv, $sourceport ) = (split /:/, $vals
+[0])[0,1];
                    my( $destserv, $destport )  = (split /:/, $vals[2]
+)[0,1];
                    my( $low, $high ) =
                      sort { $a cmp $b }
                      ( "$sourceserv:$sourceport", "$destserv:$destpor
+t" );
                    my( $key ) = $low . '-' . $high;
                    [ $key, $sourceport , $_ ]
            }
            <DATA> ){
  print $line;
}
[download]

And the output as desired:

10.10.10.5:1000 -> 10.10.10.10:8000
10.10.10.5:1000 -> 10.10.10.10:8000
10.10.10.10:8000 -> 10.10.10.5:1000
10.10.10.10:8000 -> 10.10.10.5:1000
10.10.10.10:8000 -> 10.10.10.5:1000
10.10.10.5:1001 -> 10.10.10.10:8000
10.10.10.5:1001 -> 10.10.10.10:8000
10.10.10.10:8000 -> 10.10.10.5:1001
10.10.10.6:1000 -> 10.10.10.10:8000
10.10.10.6:1000 -> 10.10.10.10:8000
10.10.10.10:8000 -> 10.10.10.6:1000
10.10.10.6:1001 -> 10.10.10.10:8000
10.10.10.6:1001 -> 10.10.10.10:8000
10.10.10.10:8000 -> 10.10.10.6:1001
10.10.10.7:1000 -> 10.10.10.10:8000
[download]

Is this efficient? I don't know. Will it run "fast enough"? Also don't know. But I suppose I could let it chug along while I'm here on a Saturday, and if it's still running after I leave, so be it :) (Please don't ask how large the capture file is ;)

Thanks much!

$,=42;for(34,0,-3,9,-11,11,-17,7,-5){$*.=pack'c'=>$,+=$_}for(reverse s
+plit//=>$*
){$%++?$ %%2?push@C,$_,$":push@c,$_,$":(push@C,$_,$")&&push@c,$"}$C[$#
+C]=$/;($#C
>$#c)?($ c=\@C)&&($ C=\@c):($ c=\@c)&&($C=\@C);$%=$|;for(@$c){print$_^
+$$C[$%++]}
[download]