For the Mail Gateway service, you can configure the access cache, event notifications, and statistics.
Configure Mail Gateway Reporting
- Open the Mail Gateway Settings page (Config > Full Config > Virtual Servers > your virtual server > Assigned Services > Mail-Gateway).
- In the left menu, select Reporting.
- Click Lock.
- In the Entries in Access Cache section, you can set the following limits on the number of access cache entries:
- Delivered Entries – The maximum number of entries for successfully delivered emails.
- Undelivered Entries – The maximum number of entries for unsuccessfully delivered emails.
In the Event Settings section, specify the event notifications that should be generated. For more information on the settings that you can configure in this section and the events that are generated when you enable each setting, expand the following Settings Overview section:
Setting Description Event Generated
Admin Reception Commands
To send an event notification when an email is blocked or allowed manually through the Allow/Block Mail Reception admin commands, select yes.
Mail Operation Changed: [user@peer] 
Admin Discard Mail Cmd
To send an event notification when an email is discarded with an admin command, select yes. Administrators with special admin permissions are allowed to discard mails in the mail queue.
Mail Data Discarded: ID [spool-ID Nr.] 
To send an event notification when incoming mail is denied according to spam filtering configurations, select yes.
Mail Relaying Denied: Deny [Rule] 
To send an event notification when an email delivery to a blacklisted recipient is refused, select yes.
Mail Delivery Refused: Drop recipient <[e-mail address of dropped recipient]>  Parallel Connection Limit
To send an event notification when the number of parallel connections to the mail gateway reaches a critical value or exceeds the mail gateway limit, select yes.
Resource Limit Pending/ Resource Limit Exceeded: Max connections (per Peer) [135/136]
To set a limit on the number of incoming mail jobs that can be queued, select yes. In the Number of Queued Mails field, enter the maximum number of emails that can be queued.
Resource Limit Pending/ Resource Limit Exceeded: Spool Limit Exceeded [135/136] Number of Queued Mails The maximum number of emails that can be queued. If the spool queue length reaches a critical value or exceeds the maximum limit, an event notification is generated.
Mail Data Size Limit
To send an event notification when the size of an email exceeds the mail gateway limit, select yes.
Mail Size Limit Exceeded 
User Defined Rule Event
To send event notifications for custom rule events, select yes.
If no custom rule events have been defined, this setting is ignored.
- Mail Rule Notice 
- Mail Rule Warning 
- Mail Rule Alert 
Bad Rulefile Loaded
To send an event notification when the rule file for the Local Domain Settings, Global Domain Parameters, and Extended Domain Setup is missing or corrupted, select yes. Mail cannot be received when this rule file is missing or corrupted.
Flawed Configuration Data Activation 
Kill Worker Process
To send an event notification when a worker process is killed, select yes.
The mail data receiving process, or worker, starts when a connection to the mail gateway is established. Worker processes can be killed with the "Kill Process" admin command. For example, when the transmission of an email with a large attachment must be stopped.
Minimum configuration: To start the Mail Gateway service on your Barracuda NG Firewall, you must specify at least an internal and external bind IP address (both IP addresses are to be configured as server IP addresses), and a postmaster address.
Subprocess Kill Requested: Kill PROC_SMTP Worker 
For more information on event notifications, see Logs, Statistics, Events.
- In the Statistic Settings section, specify the types of statistics data that should be generated. For more information on the different types of statistics, see Statistics.
- Click Send Changes and Activate.