MailStore Gateway is a supplementary tool designed for use with MailStore Server and MailStore Service Provider Edition email archiving solutions. The product provides SMTP and POP3 proxy functionality along with basic mail server functions for receiving and storing emails from cloud-based email services and other email servers. The tool enables archiving of emails from Microsoft 365, Google Workspace, and other email servers capable of sending emails to external archiving solutions via SMTP. It allows configuration and management of secure mailboxes as targets for journal and archiving rules, eliminating the need for third-party external journal mailboxes. MailStore Gateway operates in two primary scenarios. As a server, it functions as a journaling or archiving target for other email servers, receiving copies of all sent or received emails. As a proxy, it records all SMTP and POP3 traffic passing between email clients and email servers, enabling archiving for businesses without their own email server or those using services that do not support journal or archiving rules. The product includes security features such as password protection, encryption of stored data, and does not support unencrypted connections. Access to data requires the mailbox password. The POP3 server component allows MailStore Server and MailStore SPE to archive emails via standardized email transmission protocol.