I said it in the CB already:

Never use an unguarded assignment after a regex match. Always do

die "No data found" unless /...(...)/; 
my $value = $1;/
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or do

my $value; if (/...(...)/) { $value = $1 };
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In your case, this amount to:

...
    my $port = '<no port found>';
    if ($line =~/(port=([0-9]+))/i) {
        $port= $2;
    };
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