# Implement Plugin Assisted Mail Submission in a different mail server or secure email gateway

Most organizations use Exchange Server or Exchange Online as their email gateway. However, if you are using a Secure Email Gateway (SEG) such as ProofPoint or Mimecast and require outbound Zivver messages to pass through your SEG, you must meet the following requirements.

## Requirements

- The SEG must be able to [connect to the Zivver smart host](https://docs.zivver.com/en/admin/smtp/connect-to-zivver-smtp-gateway.html).
- The SEG must be able to [filter outbound email on a custom email header](https://docs.zivver.com/en/admin/officeplugin/pams/filter-outbound-zivver-messages-on-a-custom-mail-header.html).
- All emails with the `zivver-relay` header must be routed to `smtp.zivver.com`, including those sent to internal recipients.
- The SEG must not affect or remove any email headers starting with `x-zivver`.
- The `Zivver-message-info` attachment must not be altered.

[To PAMS table of contents](https://docs.zivver.com/en/admin/officeplugin/pams/pams.html)

Updated on 2026-06-18