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Connection Default Rules

System Rules

Rule name


(Locked) DHA

The (Locked) DHA Rule checks whether the email address is configured in the Mailboxes section. If the email address is not configured, then the message is rejected.

(Default) Spamhaus

Checks the IP of the sender against commercially available blacklists. This includes the XBL, SBL and PBL.

(Default) Spam RBL

Checks the IP of the sender against crowd sourced and community supported available blacklists.

(Default) Invalid MX record

This rule will only be triggered if the MX record for the domain is invalid and EMS was unable to deliver.

(Default) Zero Reputation Domain service

Identifies email domains that are newly registered or were previously dormant and will reject emails from them for a 24 hour period, excludes entries on the safe list.

Standard rules

Rule name


Maximum Mail Size

Automatically rejects emails above a certain size. The default is 50Mb, but you can easily change that limit.


Disabling this connection rule may result in emails being accepted which later cannot be released. This is due to file size compression as discussed in RFC 2045 section 6.8: Content-Transfer-Encoding

Routing Loop detection

Detects mails that are in a possible loop based on the received header count. Values available from 25-32 hops.


The Deny Rule is used to block connections from address that are entered on the Global and personal Deny lists. It will block inbound and outbound email from and to those email addresses respectively.