mpop is a POP3 client: it retrieves mail from POP3 mailboxes. In its default mode of operation, it retrieves mails from one or more POP3 mailboxes, optionally does some filtering, and delivers them through a mail delivery agent (MDA) or to maildir folders, mbox files, or Exchange pickup directories. Mails that were successfully delivered before will not be retrieved a second time, even if errors occur or mpop is terminated in the middle of a session.

Features:
1. Header based mail filtering: filter junk mail before downloading it.
2. Delivery to mbox files, maildir folders, or a mail delivery agent (MDA). Delivery with SMTP is possible by using an appropriate MDA, for example msmtp.
3. Fast POP3 implementation using command pipelining.
4. Authentication methods USER/PASS, APOP, PLAIN, LOGIN, CRAM-MD5, DIGEST-MD5, GSSAPI, and NTLM.
5. TLS/SSL both in POP3-over-SSL mode and in STARTTLS mode. Full certificate trust checks can be performed. A client certificate can be sent.
6. Support for multiple POP3 accounts.
7. Support for Internationalized Domain Names (IDN).
8. IPv6 support.

The license of this software is Free, you can free download and free use this email checker software.