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Barracuda CloudGen Firewall

This Firmware Version Is End-Of-Support

Documentation for this product is no longer updated. Please see https://campus.barracuda.com/doc/71862301/ for further information on our EoS policy.

How to Use the Mail Gateway Interface

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The following article explains the functional parameters accessible via the Barracuda NG Firewall Mail Gateway interface. For each tab there is a context menu accessible that allows specifying the settings according to your needs. 

In this article:

To access and administer operative processes on the Barracuda NG Firewall mail gateway, click MailGW in the box menu. The user interface is characterized by the following tabs:

Mail Queue Tab 

This register displays pending mail jobs. In section view mails jobs are arranged according to their spam classification state. They are classified into the following categories:

  • Spam State Unknown
  • Spam
  • No Spam

If no SPAM Filter has been configured, all e-mails are categorized as Spam State Unknown, regardless of their content.

Information on currently queued jobs covers the following:

Parameter Overview

ColumnDescription
Spam

E-mails are flagged with an icon according to their spam classification:

  • Yellow Spam State Unknown
  • Red  Spam
  • Green No Spam

From

Shows the sender address.

To

Shows the recipient(s) address(es).

Subject

Shows the mail object’s subject.

State

Shows an icon displaying the current spool activity and a corresponding state description:

  • Green Arrow – Active pending, ready for delivery and pending until MTA is ready.
  • Yellow Arrow – Active, delivery is performed right now.
  • Exclamation Mark  Give up, e-mail could not be delivered due to problems on the recipient’s side and no further delivery attempts will be undertaken.
  • Yellow bug Crash, e-mail could not be delivered due to misconfiguration (for example missing MX record, unknown recipient domain)
  • Grey data icon  Pause, delivery has been paused due to execution of the admin command Pause Delivery (see Context Menu Entries)

Prio

Shows the priority of the mail object:

  • Green Low
  • Orange Normal (default)
  • Red High
  • Clock Urgent

APrio

Shows the actual priority of the mail object. Due to high traffic a mail object can be ready for delivery but cannot be delivered yet. The object’s priority continuously rises, until it can finally be sent. Effective priorities in the APrio column are the same as in the Prio column, except for priority urgent. 

Size Shows the size of the mail object.
NumTo

Shows the number of recipients for the mail object.

Tries

Shows the tries carried out for delivering the mail object.

Last Status

Shows the last try’s status.

Next Try column

Shows waiting period until next delivery try (hh:mm:ss).

Last Try

Shows time passed since last delivery try.

Receive Time

Shows receiving time of the mail object.

Scan State

Shows an icon displaying the e-mail objects scan state. The following icons are in use.

  • Green shield E-mail scan has been completed successfully.
  • Red cross shield E-mail scan could not be executed completely and has been aborted.

Spool ID

Shows the ID of the mail object.

Context Menu Entries

Right-clicking a data set opens a context menu with commands assisting in figuring out why a mail could not be delivered and allowing influence on execution of pending mail jobs.

Execution of the commands made available through the context menu requires adequate permissions.

The following options are available:

Parameter Overview

ParameterDescription
Show Envelope

This command opens a window showing the mail envelope. The mail envelope contains information on the selected mail job, such as sender / recipient address, helo / ehlo name, mail size, scheduling priority

Show Log FileThis command opens a window showing the mail job’s log file. The log file contains information on MTA operation. 
Schedule NowIf an e-mail cannot be delivered at once, the mail gateway retries delivery according to the MTA Retry Sequence. To skip the MTA Retry Sequence select this option to start a new delivery attempt. 
Change Priority

With this option you can change scheduling priority of the selected mail job. Default scheduling priority is normal. Jobs with high priority will be scheduled first; jobs with lower priorities will be scheduled thereafter. The following scheduling priorities exist:

  • Low
  • Normal (default)
  • High
  • Urgent
Change Priority and Schedule

This option combines the two scheduling options:

  • Change Priority
  • Schedule Now
Pause/Resume Delivery

Select Pause Delivery to halt delivery of a mail job.

Select Resume Delivery to resume it.

Discard Mail

Select this option to discard a mail job and to remove the mail object from the mail queue.

Mails in active state cannot be discarded.

Access Tab

This register shows the access cache of the mail gateway service. The access cache contains completed mail jobs, which have been moved to it from the mail queue. The access cache thus represents a history of the mail gateway. The maximum number of entries the access cache may contain is specified through parameter sets MailGW Settings - Limits – see: How to Configure Mail Gateway Service Limits. Again, in section view, e-mails are arranged in groups disclosing their spam classification state. Mails are classified into the following categories:

  • Spam State Unknown
  • Spam
  • No Spam 

All columns, except the State column, can be interpreted in the same way as described in the section Mail Queue Tab. As the Access tab represents a history, the state column only knows the following three states:

  • deliver mail has been delivered successfully
  • giveup mail could not be delivered / mail has been discarded by admin command
  • crash an error has occurred during delivery or internal operation 

Furthermore, the following column pays regard to handling of suspicious and malicious attachments:

  • Stripped column A mail object is tagged with a pair of scissors, if a spam suspicious or malicious virus attachment has been removed from it.

    All attachments will be cut out from an e-mail containing multiple attachments, if only one of them is classified as suspicious file because it cannot be scanned. The virus scanner does not generate information, which of the files is the suspicious one. If of interest, a manual scan is necessary, after all attachments have been downloaded. For a definition of suspicious files, please see section: Delete All Suspicious Attachments.

Context Menu Entries

Execution of the commands made available through the context menu requires adequate permissions.

Right-clicking a group title makes the following context menu entries available:

  • Delete Items in Category Deletes all access entries from the selected category Spam State Unknown, Spam or No Spam.

    This action does not automatically delete possibly cut attachments from the Attachments tab. Right-clicking any data set makes the following context menu entries available:

  • Show Logfile / Show Envelope See above section, Context Menu Entries.
  • Remove Entry Removes the selected data set (or multiple data sets if selected).
  • Clear All Deletes all objects from the Access tab. 

Right-clicking a data set flagged with  in the Attachment Stripped column makes the following additional option available:

  • Show Stripped Attachments Clicking this item redirects the administrator to the attachment(s) cut from the mail object, now located for analysis in the Attachments tab (see below section, Attachments Tab).

Spam Tab

This tab combines Mail Queue and Access tab and only displays spam tagged e-mails. As this tab serves informational purpose only, the context menu has no tools for modification/deletion of entries. The only available actions from the context menu are:

  • Show EnvelopeOpens a view containing basic information concerning the select mail (for example mail size, peer IP address, sender,).
  • Show Log FileOpens a view containing all log files that were created by the selected mail.

    The columns building the spam list/spam tab can be interpreted in the same way like the ones used in the Mail Queue Tab and Access Tab (see above section, Access Tab).

Processes Tab

The Processes register shows the active mail gateway processes. When a multitude of processes is running, use the filter options Delivery, Receiving, and Internal in the filter section area, to limit the amount of processes shown.

Internal processes are not shown by default. Adapt the filter setting for Internal to display them.

Information on currently active processes covers the following:

Parameter Overview

ParameterDescription
PID column

Shows the Process Identifier. (Proc ID)

State column

Processes can have the following states:

  • pause (only available with type mgw_main)
  • active

Type column

The following process types exist:

  • mgw_main This is the parent process of the Barracuda NG Firewall mail gateway service. It provides the SMTP listening sockets and handles the mail receiving processes (SMTP worker processes). 
  • qspool_main This process listens for incoming connections from a remote host running the Barracuda NG Firewall administration GUI Barracuda NG Admin. 
  • qspool worker This process is responsible for transferring the visualization data (Mail Queue, Access Cache, Processes, Logs, Stats) to the remote host running the Barracuda NG Firewall administration GUI Barracuda NG Admin.
  • SMTP worker This temporary process is activated when a client opens a SMTP connection to the mail gateway. The SMTP worker process is responsible for receiving mail data from the client. It terminates when mail data transfer has ended.
  • spooler The spooler process is responsible for scheduling mail jobs. When the worker process receives a mail job, its state temporarily changes to spool. While it is in this state, the mail job is visualized in the Mail Queue tab. The mail queue becomes larger with every mail job getting spooled. The sequence, by which the spooled items are worked off, is handled by the Spooling Priority.
  • mta (Mail Transfer Agent) This process is responsible for mail delivery. When the MTA process receives a mail job from the spooler, it establishes a connection to a foreign target mail server (the mail job's recipient mail server) and delivers the e-mail. After successful delivery, the mail job moves from the mail queue to the access cache.
  • ha (High Availability) This process is needed for synchronizing mail traffic between HA partners.
Peer column

Shows peer IP and port handled by a SMTP or qspool worker.

Spool ID column

Shows the spool ID of the mail being processed by a Mail Transfer Agent (MTA).

Context Menu Entries

Execution of the commands made available through the context menu requires adequate permissions.

Right-clicking a data set makes the following context menu entries available:

  • Kill Process  With administrative permissions single worker processes can be killed. MTA processes are automatically created on demand until the configured maximum number of MTAs has been reached (see: How to Configure Advanced Mail Gateway Settings, section Mail Transfer Agents (MTAs)).

    Killing a worker process triggers the event Subprocess Kill Requested: Kill PROC_SMTP Worker [2054] when eventing is activated through parameter Kill Worker Process (default: no).

  • Allow Mail Reception Used to resume mail operation after blocking mail reception.

  • Block Mail Reception Used to block the mail gateway process. 

Attachments Tab

The Attachments tab assembles cut e-mail attachments. Its listing arranges mail objects sorted ascending by their Spool ID. Cut attachments are directly assigned to the object they have been cut from. Use this operative area to decide individually how to proceed with suspicious or malicious files.

File types meant to be cut from e-mails and not forwarded to their recipients are on the one hand defined through the virus scanner (see: Virus Scanner) and on the other hand specifically appointed through the mail gateway settings (see: How to Configure Content Stripping, Grey Listing, and Blacklists section Attachment Stripping).

Available information is arranged in the following columns:

  • Spool This column shows the e-mail's spool ID and behind it in brackets the number of attachments which has been cut from it. Click on the + symbol to display detail information regarding the attachments.
  • From Shows the sender address.
  • To Shows the recipient(s) address(es).
  • Subject Shows the mail object's subject.
  • Receive Time Shows the time the message has been arrived at the mail gateway.
  • Filename Shows the name of the file, which has been cut.
  • Reason Displays the reason why the file has been cut.
Context Menu Entries

Right clicking any data set makes the following context menu entries available:

Parameter Overview

ParameterDescription

Delete All Attachments

Deletes all attachments from all mail objects currently assembled in the listing regardless of the reason why they have been cut.

Delete All Normal Attachments

If the mail gateway has been configured to cut all file attachments regardless of their type (see: How to Configure Content Adaptions, section Attachment Stripping), they will be contained in this tab. This action deletes all mail attachments, which have been stripped off according to mail gateway settings.

Delete All Suspicious Attachments

Deletes all file attachments, which have been classified as suspicious by the virus scanner. Files are classified as suspicious when the virus scanner for any reason is not able to handle them properly. Amongst others, the following can be causes for this:

  • The file attachment is larger than 1 MB and thus cannot be scanned completely.
  • The file attachment is encrypted.
  • The file attachment is an archive file exceeding the maximum allowed archive size.
Delete All Virus Attachments

Deletes all malicious file attachments like viruses.

Right-clicking a Spool ID header makes the following action available:

  • Delete Attachments From This MailDeletes all attachments from the selected mail object.

Right-clicking a selected file object makes the following actions available:

  • Get Attachment Makes the cut attachment available for download. It is up to the respective administrator to download the file to his/her own harddisk, scan the file manually and thereafter possibly forward it to the original recipient.
  • Delete Attachment Deletes the selected file attachment.

Continue with: How to Use the Grey Listing Tab.

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