File Coverage

lib/Sisimai/Rhost/Mimecast.pm

Criterion	Covered	Total	%
statement	25	25	100.0
branch	6	8	75.0
condition	4	6	66.6
subroutine	4	4	100.0
pod	0	1	0.0
total	39	44	88.6

package Sisimai::Rhost::Mimecast;
use feature ':5.10';
use strict;
use warnings;

sub get {
    # Detect bounce reason from https://www.mimecast.com/
    # @param    [Sisimai::Data] argvs   Parsed email object
    # @return   [String]                The bounce reason at Mimecast
    # @since v4.25.15
    my $class = shift;
    my $argvs = shift // return undef;

    return undef unless length $argvs->{'diagnosticcode'};
    return undef unless $argvs->{'replycode'} =~ /\A[245]\d\d\z/;

    state $messagesof = {
        # https://community.mimecast.com/s/article/Mimecast-SMTP-Error-Codes-842605754
        'blocked' => [
            # - The sender's IP address has been blocked by a Blocked Senders Policy.
            # - Remove the entry from the policy.
            [421, 'sender address blocked'],

            # - The Sender's IP address has been placed on the block list due to too many invalid
            #   connections.
            # - The sender's mail server must retry the connection. The mail server performing the
            #   connection says the recipient address validation isn't responding.
            [451, 'recipient temporarily unavailable'],

            # - You've reached your mail server's limit.
            # - Wait and try again. The mail server won't accept any messages until you're under
            #   the limit.
            [451, 'ip temporarily blacklisted'],

            # - The sending mail server is subjected to Greylisting. This requires the server to
            #   retry the connection, between one minute and 12 hours. Alternatively, the sender's
            #   IP address has a poor reputation.
            # - These reputation checks can be bypassed with an Auto Allow or Permitted Senders
            #   policy. If it's legitimate traffic, amend your Greylisting policy.
            [451, 'internal resources are temporarily unavailable'],

            # - Ongoing reputation checks have resulted in the message being rejected due to poor
            #   IP reputation. This could occur after a 4xx error.
            # - Create an Auto Allow or Permitted Senders policy.
            #   Note:
            #     You can request a review of your source IP ranges by completing our online form.
            [550, 'local ct ip reputation - (reject)'],

            # - The sender's IP address is listed in an RBL. The text displayed is specific to the
            #   RBL which lists the sender's IP address.
            # - Bypass the RBL with an Auto Allow or Permitted Senders policy. Additionally request
            #   the associated IP address from the RBL.
            #[550, '< details of RBL >'], NEED AN ACTUAL ERROR MESSAGE STRING

            # - The inbound message has been rejected because the originated IP address isn't list-
            #   ed in the published SPF records for the sending domain.
            # - Ensure all the IP addresses for your mail servers are listed in your SPF records.
            #   Alternatively, create a DNS Authentication (Inbound / Outbound) policy with the
            #   "Inbound SPF" or "Reject on Hard Fail" option disabled. Messages that fail our SPF
            #   checks are subjected to spam and RBL checks, instead of being rejected.
            [550, 'spf sender invalid - envelope rejected'],

            # - The DKIM key for the outbound message is broken and doesn't match the DNS record of
            #   the registered sender.
            # - Check your organization's DNS record is populated with the right public key as part
            #   of the DNS Authentication Outbound Signing definition. The private key of the key-
            #   pair must be populated in the DNS Authentication policy, along with the domain and
            #   selector of that record.
            [550, 'dkim sender invalid - envelope rejected'],

            # - The inbound message has been rejected because the originated IP address isn't list-
            #   ed in the published SPF records for the sending domain.
            # - Ensure all the IP addresses for your mail servers are listed in your SPF records.
            [550, 'dmarc sender invalid - envelope rejected'],
        ],
        'mesgtoobig' => [
            # - The email size either exceeds an Email Size Limit policy or is larger than the
            #   Mimecast service limit. The default is 100 MB for the Legacy MTA, and 200 MB for
            #   "the Latest MTA".
            # - Resend the message ensuring it's smaller than the limitation set. The transmission
            #   and content-encoding can add significantly to the total message size (e.g. a mes-
            #   sage with a 70 MB attachment, can have an overall size larger than 100 MB).
            [554, 'maximum email size exceeded'],
        ],
        'networkerror' => [
            # - The message has too many "received headers" as it has been forwarded across multi-
            #   ple hops. Once 25 hops have been reached, the email is rejected.
            # - Investigate the email addresses in the communication pairs, to see what forwarders
            #   are configured on the mail servers.
            [554, 'mail loop detected'],
        ],
        'norelaying' => [
            # - Both the sender and recipient domains specified in the transmission are external to
            #   Mimecast, and aren't allowed to relay through the Mimecast service and/or the con-
            #   necting IP address isn't recognized as authorized.
            # - Mimecast customers should contact Mimecast Support to add the Authorized Outbound
            #   address, or to take other remedial action.
            [451, 'open relay not allowed'],
        ],
        'notaccept' => [
            # - The customer account Inbound emails are disabled in the Administration Console.
            # - Contact Mimecast Support if the account's inbound traffic should be allowed.
            [451, 'account inbounds disabled'],
        ],
        'onhold' => [
            # - The customer account outbound emails are disabled in the Administration Console.
            # - Contact Mimecast Support if the account's outbound traffic should be allowed.
            [451, 'account outbounds disabled'],

            # - Omni Directional hostnames are enabled.
            # - Disable Omni Directional hostnames.
            [451, 'hostname is not authorized'],

            # - Attempts are being made to journal mail that is past the set expiry threshold. The
            #   failure will be replaced by a retry response because the message is marked for re-
            #   try if rejected, causing the journal queue to grow.
            # - Check to confirm there are no significant time discrepancies on the mail server.
            #   Discontinue journaling old messages past the expiry threshold.
            [550, 'journal message past expiration'],
        ],
        'policyviolation' => [
            # - The message has triggered an Anti-Spoofing policy.
            # - Create an Anti-Spoofing policy to take no action for the sender's address or IP ad-
            #   dress.
            [550, 'anti-spoofing policy - inbound not allowed'],
            [550, 'rejected by header-based anti-spoofing policy'],

            # - The message has triggered a Content Examination policy.
            # - Either create a Content Examination Bypass policy or adjust the Content Examination
            #   policy as required.
            [550, 'message bounced due to content examination policy'],

            # - The message has triggered a Geographical Restriction policy.
            # - Delete or amend the policy.
            [554, 'host network not allowed'],
        ],
        'rejected' => [
            # - The sender's email address or domain has triggered a Blocked Senders Policy or
            #   there's an SPF hard rejection.
            # - Delete or modify the Blocked Senders policy to exclude the sender address.
            [550, 'administrative prohibition envelope blocked'],

            # - A personal block policy is in place for the email address/domain.
            # - Remove the email address/domain from the Managed Senders list.
            [550, 'envelope blocked – user entry'],
            [550, 'envelope blocked – user domain entry'],
            [550, 'rejected by header-based manually blocked senders - block for manual block'],

            # - A Block Sender Policy has been applied to reject emails based on the Header From or
            #   Envelope From address.
            # - Delete or change the Blocked Senders policy.
            [550, 'rejected by header-based blocked senders - block policy for header from'],
            [550, 'envelope rejected - block policy for envelope from address'],
        ],
        'securityerror' => [
            # - Messages submitted to SMTP port 587 require authentication. This error indicates
            #   the authentication details provided were incorrect.
            # - Check your authentication details match an internal email address in Mimecast, with
            #   a corresponding Mimecast cloud password. Alternatively, consider sending the mes-
            #   sage on SMTP port 25.
            [535, 'incorrect authentication data'],
            [550, 'submitter failed to disabled'],

            # - This email has been sent using SMTP, but TLS is required by policy.
            # - Delete or change the Secure Receipt or Secure Delivery policy enforcing TLS.
            #   Alternatively, ensure the certificates on the mail server haven't expired. If using
            #   a proxy server, ensure it isn't intercepting the traffic and modifying encryption
            #   parameters.
            [553, 'this route requires encryption (tls)'],

            # - A TLS connection has been attempted using a TLS version that is lower than TLS 1.2.
            # - Delete or change the Secure Receipt or Secure Delivery policy enforcing TLS.
            #   Alternatively, ensure the mail server attempting to connect is using the appropri-
            #   ate version of TLS.
            [553, 'this route requires tls version 1.2 or greater'],

            # - A secure connection was attempted using ciphers that do not meet the configured ci-
            #   pher strength.
            # - Delete or change the Secure Receipt or Secure Delivery policy enforcing TLS. Alter-
            #   natively, ensure the certificates on the mail server haven't expired. If using a
            #   proxy server, ensure it isn't intercepting the traffic and modifying encryption
            #   parameters.
            [553, 'this route requires high-strength ciphers'],

            # - Validation on your umbrella account's domain name does not conform to your DNS.
            # - Check you DNS has the required umbrella accounts listed as comma-separated values.
            [554, 'configuration is invalid for this certificate'],
        ],
        'systemerror' => [
            # - The Mimecast server is under maximum load.
            # - No action is required from the end-user. The message will retry 30 times and when
            #   server resources are available, the message is processed.
            [451, 'unable to process connection at this time'],

            # - The message was incorrectly terminated. This can be caused by:
            #   - Files that previously contained a virus, but haven't been cleaned by an anti-virus
            #     product, leaving traces in the message.
            #   - Firewall issues on the sender's side.
            #   - Incorrectly configured content rules on a security device.
            # - Investigate the Intrusion Detection software or other SMTP protocol analyzers. If
            #   running a Cisco Firewall, ensure the Mail- guard or SMTP Fixup module is disabled.
            [451, 'message ended early'],

            # - Generic error if the reason is unknown
            # - Contact Mimecast Support.
            [451, 'unable to process command'],

            # - Generic error if the reason is unknown
            # - Contact Mimecast Support.
            [451, 'unable to process an email at this time'],
        ],
        'toomanyconn' => [
            # - There are too many concurrent inbound connections for the account. The default is 20.
            # - The IP address is automatically removed from the block list after five minutes.
            #   Continued invalid connections result in the IP being readded to the block list. En-
            #   sure you don't route outbound or journal messages to Mimecast from an IP address
            #   that hasn't been authorized to do so.
            [451, 'account service is temporarily unavailable'],

            # - The sending server issues more than 100 RCPT TO entries. By default, Mimecast only
            #   accepts 100 RCPT TO entries per message body (DATA). The error triggers the sending
            #   mail server to provide the DATA for the first 100 recipients before it provides the
            #   next batch of RCPT TO entries.
            # - Most mail servers respect the transient error and treat it as a "truncation request".
            #   If your mail server, firewall, or on-site solution doesn't respect the error, you
            #   must ensure that no more than 100 recipients are submitted.
            #   Note:
            #       Solutions like SMTP Fix-Up / MailGuard and ESMTP inspection on Cisco Pix and
            #       ASA Firewalls are known not to respect the transient error. We advise you to
            #       disable this functionality.
            [452, 'too many recipients'],

            # - There are too many concurrent outbound connections for the account.
            # - Send the messages in smaller chunks to recipients.
            [550, 'exceeding outbound thread limit'],
        ],
        'userunknown' => [
            # - The email address isn't a valid SMTP address.
            # - The sender must resend the message to a valid internal email address.
            [501, 'invalid address'],

            # - The server has encountered a bad sequence of commands, or it requires an authenti-
            #   cation.
            # - In case of a "bad sequence", the server has pulled off its commands in the wrong
            #   order, usually because of a broken connection. If authentication is needed, enter
            #   your username and password.
            [503, 'user unknown'],

            # - Known recipient, LDAP, or SMTP call forwarding recipient validation checks haven't
            #   returned a valid internal user.
            # - The sender must resend the message to a valid internal recipient address.
            [550, 'invalid recipient'],
        ],
        'virusdetected' => [
            # - A signature was detected that could either be a virus, or a spam score over the
            #   maximum threshold. The spam score isn't available in the Administration Console. If
            #   you aren't a Mimecast customer but have emails rejected with this error code, con-
            #   tact the recipient to adjust their configuration and permit your address. If unsuc-
            #   cessful, your IT department can submit a request to review these email rejections
            #   via our Sender Feedback form.
            # - Anti-virus checks cannot be bypassed. Contact the sender to see if they can stop
            #   these messages from being blocked. Anti-spam checks can be bypassed using a Per-
            #   mitted Senders or Auto Allow policy. Rejected emails can be viewed in your Outbound
            #   Activity and searching for the required email address.
            [554, 'email rejected due to security policies'],
        ],
    };

    my $esmtperror = lc  $argvs->{'diagnosticcode'} // 0;
    my $esmtpreply = int $argvs->{'replycode'}      // 0;
    my $reasontext = '';

    REASON: for my $e ( keys %$messagesof ) {
        # Try to find with each error message defined in $messagesof
        for my $f ( @{ $messagesof->{ $e } } ) {
            # Find an error reason
            next unless $esmtpreply == $f->[0];
            next unless index($esmtperror, $f->[1]) > -1;
            $reasontext = $e;
            last REASON;
        }
    }
    return $reasontext;
}

1;
__END__