The smartmatch table in perlop explains what ~~ does for a HASH and ARRAY:
HASH ~~ ARRAY : any ARRAY elements exist as HASH keys (like: grep { exists HASH->{$_} } ARRAY)

Update: If you want to get unique nodes and ports, use a hash of hashes: 

$href->{$node}{$port} = 1;

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لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In reply to Re: Removing duplicate hashrefs from an array by choroba
in thread Removing duplicate hashrefs from an array by msomanat

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