# Above all others, add:
use strict;

# Some stuff here

my %connection = (
    pop3 => {
        PeerAddr => 'mail.test.com',
        PeerPort => 110,
    },
# Add the others here, like above
);

my %socket;
while (my ($name, $values) = each %connections)
{
    $socket{$name} = IO::Socket::INET->new(
        Timeout  => 1,
        Proto    => 'tcp',
        ( map { $_ => $values->{$_} } keys %$values ),
    );
}

my $UP   = 'Up';
my $DOWN = 'Down';

my $mail = ($socket{pop3} && $socket{smtp}
    ? $UP
    : $DOWN);

# Do other checks here