NAME

Qpsmtpd::DSN - Enhanced Mail System Status Codes - RFC 1893

DESCRIPTION

The Qpsmtpd::DSN implements the Enhanced Mail System Status Codes from RFC 1893.

USAGE

Any qpsmtpd plugin can access these status codes. All sub routines are used the same way:
use Qpsmtpd::DSN;
...;
return Qpsmtpd::DSN->relaying_denied();

or

 return Qpsmtpd::DSN->relaying_denied("Relaying from $ip denied");

or

 return Qpsmtpd::DSN->relaying_denied(DENY,"Relaying from $ip denied");

If no status message was given, it will use the predefined one from the RFC. If the first argument is numeric, it will use this as a return code, else the default return code is used. See below which default return code is used in the different functions.

The first example will return (DENY, "Relaying denied"); the others (DENY, "Relaying from $ip denied"); which will be returned to qpsmtpd.

In those sub routines which don't start with addr_, sys_, net_, proto_, media_, sec_ I've added a default message which describes the status better than the RFC message.

ADDRESS STATUS

addr_unspecified

X.1.0 default: DENYSOFT

no_such_user, addr_bad_dest_mbox

X.1.1 default: DENY

addr_bad_dest_system

X.1.2 default: DENY

addr_bad_dest_syntax

X.1.3 default: DENY

addr_dest_ambigous

X.1.4 default: DENYSOFT

addr_rcpt_ok

X.1.5 default: OK

addr_mbox_moved

X.1.6 default: DENY

addr_bad_from_syntax

X.1.7 default: DENY

addr_bad_from_system

X.1.8 default: DENY

MAILBOX STATUS

mbox_unspecified

X.2.0 default: DENYSOFT

mbox_disabled

X.2.1 default: DENY ...but RFC says:
The mailbox exists, but is not accepting messages. This may
be a permanent error if the mailbox will never be re-enabled
or a transient error if the mailbox is only temporarily
disabled.

mbox_full

X.2.2 default: DENYSOFT

mbox_msg_too_long

X.2.3 default: DENY

mbox_list_expansion_problem

X.2.4 default: DENYSOFT

MAIL SYSTEM STATUS

sys_unspecified

X.3.0 default: DENYSOFT

sys_disk_full

X.3.1 default: DENYSOFT

sys_not_accepting_mail

X.3.2 default: DENYSOFT

sys_not_supported

X.3.3 default: DENYSOFT
Selected features specified for the message are not
supported by the destination system. This can occur in
gateways when features from one domain cannot be mapped onto
the supported feature in another.

sys_msg_too_big

X.3.4 default DENY

NETWORK AND ROUTING STATUS

net_unspecified

X.4.0 default: DENYSOFT

net_directory_server_failed, temp_resolver_failed

X.4.3 default: DENYSOFT

net_system_congested

X.4.5 default: DENYSOFT

net_routing_loop, too_many_hops

X.4.6 default: DENY, but RFC says:
A routing loop caused the message to be forwarded too many
times, either because of incorrect routing tables or a user
forwarding loop. This is useful only as a persistent
transient error.

Why do we want to DENYSOFT something like this?

MAIL DELIVERY PROTOCOL STATUS

proto_unspecified

X.5.0 default: DENYSOFT

proto_invalid_command

X.5.1 default: DENY

proto_syntax_error

X.5.2 default: DENY

proto_rcpt_list_too_long, too_many_rcpts

X.5.3 default: DENYSOFT

proto_invalid_cmd_args

X.5.4 default: DENY

proto_wrong_version

X.5.5 default: DENYSOFT

MESSAGE CONTENT OR MESSAGE MEDIA STATUS

media_unspecified

X.6.0 default: DENYSOFT

media_unsupported

X.6.1 default: DENY

media_conv_prohibited

X.6.2 default: DENY

media_conv_unsupported

X.6.3 default: DENYSOFT

media_conv_lossy

X.6.4 default: DENYSOFT

SECURITY OR POLICY STATUS

sec_unspecified

X.7.0 default: DENYSOFT

sec_sender_unauthorized, bad_sender_ip, relaying_denied

X.7.1 default: DENY

sec_list_dest_prohibited

X.7.2 default: DENY

sec_conv_failed

X.7.3 default: DENY

sec_feature_unsupported

X.7.4 default: DENY

sec_crypto_failure

X.7.5 default: DENY

sec_crypto_algorithm_unsupported

X.7.6 default: DENYSOFT

sec_msg_integrity_failure

X.7.7 default: DENY