node1.mailcorvid.com

This host performs email address verification from 54.159.179.19. It checks whether mailboxes exist so that mail is not sent to invalid addresses.

No mail is delivered from this host. Verification opens an SMTP connection, issues MAIL FROM and RCPT TO, and then disconnects with RSET/QUIT. The DATA command is never sent, so no message body is ever transmitted.

Why you might see this host

Your mail server received an SMTP connection from this IP that asked whether an address accepts mail and then disconnected without sending anything. The purpose is list hygiene: removing dead addresses reduces bounce traffic to your servers.

Rate limits

Connections are rate limited per provider, 4xx deferrals are honoured with exponential backoff, and 421 responses end the session immediately. If this host is being noisier than you would like, tell us and we will lower it.

Contact

Both addresses are monitored:

To have this IP stop contacting your servers entirely, mail abuse@node1.mailcorvid.com with the domains concerned and they will be excluded.