The Account Classes Tab > Send/Receive Restrictions sub-page enables system administrators to define and enable or disable sending and receiving restrictions that can limit the domains and subdomains emails are sent to or received from. Additionally, they can create limited lists of recipients and senders that can or cannot send/receive emails.

The administrator defines the following options:
- Enable/Disable sending restrictions
- Allow sending only to the same domain
- Allow sending to subdomains
- Allow only recipients /Disallow recipients
- Allow sending only to the same domain
- Enable/Disable receiving restrictions
- Allow receiving only from the same domain
- Allow receiving from subdomains
- Allow only originators /Disallow originators
- Allow receiving only from the same domain
Restrictions apply for messages sent from:
- WebMail: An NDR will be returned if the destination address is not allowed.
- SMTP/Outlook Connector: The 'RCPT TO' command will yield a permanent error, if matched.
- Sendmail wrapper: An NDR will be returned if the destination address is not allowed.
