How to filter data from SQL that appears only once?

Here is an example of my SQL structure

SQL Example

As you can see 2 IPs appear only one time each, so I would like to count only these IPs.
I don’t want to count any IP address that appear more than once. How can I achieve that ?
I believe the COUNT(DISTINCT ip) will output 4, but I am expecting 2

The following code gives total count of rows in last 30 days,

$result = $dbh->query('SELECT count(*) as total from data_able WHERE dtime > DATE_SUB(CURDATE(), INTERVAL 30 DAY)');
$total = $result->fetchColumn();

How can I modify it to count unique IPs that appear only 1 time in the last 30 days.