Is liev.de valid?

Domain: liev.de

Valid: Yes, but should be blocked

This domain is valid and should be able to receive e-mail.

Tested MX: localhost (127.0.0.1)

Using MX pointer localhost from DNS with priority: 0

Block: Yes

You should block this domain for signups/registrations.

Disposable: No

This does not look like a temporary/disposable e-mail domain.

Raw API reason:

Local or non-routable IP

START USING FREE API