gist/gists/rspamd-rule-only-one-recp-2025-04-16.md

How to Make a Mailbox in Mailcow Only be Able to Send to One Recipient

Go to admin panel and add this rSpamD settings rule:

priority = 10;
from = "sender@example.com";
rcpt = "/^(?!receiver@example\.com).*$/";
apply "default" {
  MAILCOW_BLACK = 9999.0;
  message = "sender@example.com can only send to receiver@example.com";
}
symbols [
  "MAILCOW_BLACK"
]

You're welcomee!!