Enhanced Status Codes

The Enhanced Mail System Status Codes are defined in RFC 3463 except as noted.

In combination with other information provided in the Delivery Status Notification (DSN) delivery report, these codes facilitate media and language independent rendering of message delivery status.

Structure

Class Sub-code

2.XXX.XXX Success

Success specifies that the DSN is reporting a positive delivery action. Detail sub-codes may provide notification of transformations required for delivery.

4.XXX.XXX Persistent Transient Failure

A persistent transient failure is one in which the message as sent is valid, but persistence of some temporary condition has caused abandonment or delay of attempts to send the message. If this code accompanies a delivery failure report, sending in the future may be successful.

5.XXX.XXX Permanent Failure

A permanent failure is one which is not likely to be resolved by resending the message in the current form. Some change to the message or the destination must be made for successful delivery.

x.0.xxx Other or Undefined Status

There is no additional subject information available.

x.0.0
Other or Undefined Status

x.1.xxx Addressing Status

The address status reports on the originator or destination address. It may include address syntax or validity. These errors can generally be corrected by the sender and retried.

x.1.0
Other address status
x.1.1
Bad destination mailbox address
x.1.2
Bad destination system address
x.1.3
Bad destination mailbox address syntax
x.1.4
Destination mailbox address ambiguous
x.1.5
Destination address valid
x.1.6
Destination mailbox has moved, No forwarding address
x.1.7
Bad sender's mailbox address syntax
x.1.8
Bad sender's system address

x.2.xxx Mailbox Status

Mailbox status indicates that something having to do with the mailbox has caused this DSN. Mailbox issues are assumed to be under the general control of the recipient.

x.2.0
Other or undefined mailbox status
x.2.1
Mailbox disabled, not accepting messages
x.2.2
Mailbox full
x.2.3
Message length exceeds administrative limit
x.2.4
Mailing list expansion problem

x.3.xxx Mail System Status

Mail system status indicates that something having to do with the destination system has caused this DSN. System issues are assumed to be under the general control of the destination system administrator.

x.3.0
Other or undefined mail system status
x.3.1
Mail system full
x.3.2
System not accepting network messages
x.3.3
System not capable of selected features
x.3.4
Message too big for system
x.3.5
System incorrectly configured

x.4.xxx Network and Routing Status

The networking or routing codes report status about the delivery system itself. These system components include any necessary infrastructure such as directory and routing services. Network issues are assumed to be under the control of the destination or intermediate system administrator.

x.4.0
Other or undefined network or routing status
x.4.1
No answer from host
x.4.2
Bad connection
x.4.3
Directory server failure
x.4.4
Unable to route
x.4.5
Mail system congestion
x.4.6
Routing loop detected
x.4.7
Delivery time expired

x.5.xxx Mail Delivery Protocol Status

The mail delivery protocol status codes report failures involving the message delivery protocol. These failures include the full range of problems resulting from implementation errors or an unreliable connection.

x.5.0
Other or undefined protocol status
x.5.1
Invalid command
x.5.2
Syntax error
x.5.3
Too many recipients
x.5.4
Invalid command arguments
x.5.5
Wrong protocol version

x.6.xxx Message Content or Media Status

The message content or media status codes report failures involving the content of the message. These codes report failures due to translation, transcoding, or otherwise unsupported message media. Message content or media issues are under the control of both the sender and the receiver, both of which must support a common set of supported content-types.

x.6.0
Other or undefined media error
x.6.1
Media not supported
x.6.2
Conversion required and prohibited
x.6.3
Conversion required but not supported
x.6.4
Conversion with loss performed
x.6.5
Conversion Failed
x.6.6
Message content not available Source

x.7.xxx Security or Policy Status

The security or policy status codes report failures involving policies such as per-recipient or per-host filtering and cryptographic operations. Security and policy status issues are assumed to be under the control of either or both the sender and recipient. Both the sender and recipient must permit the exchange of messages and arrange the exchange of necessary keys and certificates for cryptographic operations.

x.7.0
Other or undefined security status
x.7.1
Delivery not authorized, message refused
x.7.2
Mailing list expansion prohibited
x.7.3
Security conversion required but not possible
x.7.4
Security features not supported
x.7.5
Cryptographic failure
x.7.6
Cryptographic algorithm not supported
x.7.7
Message integrity failure
x.7.8
Trust relationship required Source
x.7.16
Future release per-user message quota exceeded Source
x.7.17
Future release system message quota exceeded Source