Virus Scanner

Installing External Filter Software Starting the External Filter Using the External Filter This section explains how CommuniGate Pro can use third-party products (plugins) to scan all messages (virus protection, content filtering). The CommuniGate Pro Filter plugins provide a much more solid solution than various stand-alone SMTP-based "mail scanners": Stand-alone "scanner" SMTP servers usually implement only the basic SMTP functions. Since all SMTP connections have to be established to those servers, and not to the CommuniGate Pro SMTP module, the CommuniGate Pro SMTP extended functionality becomes unavailable to users and other SMTP servers. Stand-alone "scanner" SMTP servers usually provide much weaker performance and reliability compared to the CommuniGate Pro Servers. When the "scanner" server goes down, the CommuniGate Pro SMTP functionality becomes unavailable, too. Stand-alone "scanner" SMTP servers usually cannot scan several messages simultaneously, so when a large message is being scanned, the SMTP traffic to the CommuniGate Pro Server stops. Stand-alone "scanner" SMTP servers cannot scan messages not submitted via SMTP. For example, messages composed using the WebUser Interface and directed to a user on the same CommuniGate Pro Server are delivered bypassing any SMTP transfer operations. The CommuniGate Pro Plugins run alongside the CommuniGate Pro Server. They do not deal with message transfer protocols. Instead, the CommuniGate Pro Server passes them a message file right before the message is being enqueued into module queues. As a result, all messages can be scanned, not only the messages sent via a particular mail transfer protocol. If the CommuniGate Pro ENQUEUER is configured to use several processors (threads), several messages can be scanned simultaneously. As a result, long messages that require several seconds of scanning time do not stop the message flow. The third-party plugins usually require an additional License Key. The following filtering programs are available now: McAfee Virus Scanner for CommuniGate Pro

---

Installing External Filter Software

External Filter Software usually consists of several files - the filter program, the libraries that program uses, and various data files (virus definition files, content specificaiton files, etc.).

The External Filter Software should be downloaded either from the Stalker Software Web and/or FTP servers, or directly from the manufacturer servers. The downloaded archive should be unpacked and moved to the appropriate location on the CommuniGate Pro Server system. The CommuniGate Pro base directory is a recommended location for the External Filter Software directories.

After the software directory is stored on the CommuniGate Pro Server system, learn and remember the path to the Filter Program. If you stored the Filter Directory outside the CommuniGate Pro base directory, you should use the full path name.

McAfee Virus Scanner

The Filter Directory is called CGPMcAfee, the Filter Program is called CGPMcAfee (CGPMcAfee.exe for the MS Windows platforms).

---

Starting the External Filter

When the External Filter Software is installed, you should tell CommuniGate Pro to start the Filter Program and to establish a communication link with it. Open the General page in the Settings section of the WebAdmin Interface, and click the Helpers link. The Helpers page is displayed:

Content Filtering
Log: Crashes OnlyFailuresMajor & FailuresProblemsLow LevelAll Info Program Path:

Log

Use this setting to specify the type of information the External Filtering module should put in the Server Log. Usually you should use the Problems Log level (status change and non-fatal errors). But when you experience problems with the External Filter program, you may want to set the Log setting to Low-Level or All Info: in this case the inter-program protocol-level details will be recorded in the System Log as well.
The External Filter records in the System Log are marked with the EXTFILTER tag.

Program Path

Use this setting to specify the file name path for the External Filter program. If the External Filter Software has been installed inside the CommuniGatePro base directory, you can use the relative path (CGPMcAfee\CGPMcAfee.exe, for example). Otherwise, use the full path (such as D:\Programs\CGPMcAfee\CGPMcAfee.exe).

Note: always use the backslash (\) path separators if the CommuniGate Pro Server runs on one of the Microsoft Windows platforms.

Select the check box and click the Update button to start the External Filter program. If the program cannot be started, an error message appears on the Helpers page.

---

Using the External Filter

An enabled External Filter is not used for scanning mail messages by default. To make the Filter scan all or some messages, create a Server-Wide Rule.

If you want to scan all messages that are transferred with your CommuniGate Pro Server, do not specify any condition in that Rule. Alternatively, you can specify a Rule condition that checks the message size (for example), and performs message scanning only if the message size is larger than the specified limit:

Data Operation Parameter ---FromSenderReturn-PathToCcAny To or CcEach To or CcReply-To'From' NameSubjectMessage-IdMessage SizeTime Of DayCurrent DateCurrent DayHuman GeneratedHeader FieldAny RecipientEach RecipientAny RouteEach Route isis notinnot ingreater thanless than ---FromSenderHuman Generated isis notinnot ingreater thanless than

Action Parameters ---Write To LogExecuteFingerNotifyExternalFilterRedirect toForward toMirror toReply withReply to All withReact withStore inMarkAdd HeaderReject withDiscardStop Processing ---Write To LogExecuteFingerNotifyExternalFilterReply to All with

External Filters are contacted from the ENQUEUER threads. Since it can take serveral seconds to process a large message, increase the number of ENQUEUER processors (threads) using the Obscure page in the WebAdmin Settings section. This allows the CommuniGate Pro Server to proceed with the message enqueueing process even when a large message scan is in progress.