Given the data you've shown I'm sure not you need the first split (check for what split uses as a default).

#!/usr/bin/perl

#use v5.12.2;
use strict;
use warnings;

while(my $line = <DATA>){
    chomp $line;
    my @nums = split(/\./, $line);
    print "@nums\n";
}

__DATA__
1.2.56.3
3.55.7.3
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