Anti-Virus

ISMail can run an external anti-virus scanner to scan each incoming and outgoing mail message. Scanning messages is typically more efficient than scanning every file opened on the server by a real-time anti-virus monitor. Alternatively, different anti-virus scanners can be used on the system and with ISMail for additional virus protection.

Anti-Virus Configuration Options

ISMail supports general anti-virus options and options for specific anti-virus scanners as described below.

Path to the scanner: the complete pathname of the anti-virus executable file is specified by this option (default: none).

Arguments: virus-scanner specific input arguments. These are typically used to run the scanner in 'silent' mode and to specifiy that only mail files should be scanned (default: none).

Check Return Code: some anti-virus scanners return a value after scanning a file in addition to, or in place of, deleting the file. These values are specified by this option (default: none).

Notify Sender If Virus Found: if this option is on and a message is received by ISMail and a virus is found, then the sender of the message will be notified (default: off)

Notify Recipient If Virus Found: if this option is on and a message is received by ISMail and a virus is found, then the recipient(s) of the message will be notified (default: off).

Note: if a message is received by ISMail, the options above specify whether the sender and/or recipient(s) should be notified. However, if a message is sent using ISMail the message will be 'bounced' to the sender if a virus is found. The intended message recipients will not be notified (since the message is 'bounced' back to the sender before being sent).

Show Virus Scan Hidden Window: if a virus scanner is not working properly, this option can be turned on to display the 'hidden' DOS window used to execute the scanner in order to find the problem (default: off).

Scan Entire Messages For Viruses: if this option is on, then entire messages will be scanned. Otherwise, each message will be separated into parts and each part scanned separately (default: on).

Adding an Anti-Virus Scanner:

The Anti-Virus menu tab in the ISMail Configuration sheets is used to specify an anti-virus scanner to run on each message.

To add a scanner:

  1. Right-click the program icon located in the lower-right portion of the screen (notification area of system tray), and select 'Open'.
  2. Select the 'Anti-Virus' tab.
  3. Select the 'Anti-Virus Scanner Active' checkbox.
  4. Enter the pathname of the scanner, or use the Browse button to locate it.
  5. Enter the arguments for the scanner. A '%f' should be used to pass the filename to the scanner (ISMail will replace the '%f' with the correct filename when the scanner is run).
  6. If the return code from the scanner is used to indicate that a virus was found, select the 'Check Return Code' checkbox and enter the value(s) to be checked. Multiple values may be specified by separating each by a comma; ranges may be specified using a dash; an asterisk may be used to represent any value (e.g. '1-*' means all values greater than or equal to 1). Otherwise, ISMail assumes a virus is found if the file passed to the scanner is deleted by the scanner.
  7. If recipient should be notified upon detection of a virus, select 'Notify Recipient If Virus Found'.
  8. If sender should be notified upon detection of a virus, select 'Notify Sender If Virus Found'. (Note: this option is mainly used to notify ISMail users who inadvertently send a virus. Viruses originating outside of ISMail are often from invalid email addresses).
  9. Click 'Apply'.
  10. Exit and restart ISMail.

Note: if the anti-virus scanner does not appear to be working properly, the 'Show Virus Scan Hidden Window' box can be checked. This may require user intervention to manually close the window on each virus scan, but will display messages from the anti-virus scanner.

Example: F-Prot AntivirusTM for Windows NT/2000/XP (http://www.f-prot.com) :

  1. Download and install the anti-virus program (as soon as it is working, we recommend that you Register it and update to the latest version).
  2. Disable the anti-virus program on the desktop (i.e. disable the 'On-Demand' scanner and the scheduler. No anti-virus icon should appear in the tray or it will interfere with the anti-virus scanner in the mail server!).
  3. Enter the complete pathname of the file: fpcmd.exe.
  4. Enter the scanner arguments: /AUTO /DISINF /DELETE /NOBOOT /NOMEM /SILENT %f
  5. Select 'Check Return Code' and enter the values: 3,6 (Note: see product documentation for description of all return values).
  6. If you wish the recipient to receive notification of viruses, select 'Notify Recipient If Virus Found'.
  7. If you wish the sender to receive notification of viruses, select 'Notify Sender If Virus Found'.
  8. Click 'Apply'.
  9. Exit and restart ISMail.

Note: F-Prot must be Registered and kept updated or failures will eventually occur.

Example: F-Prot AntivirusTM for Windows 95/98/ME (http://www.f-prot.com):

  1. Download and install the anti-virus program (as soon as it is working, we recommend that you Register it and update to the latest version).
  2. Disable the anti-virus program on the desktop (i.e. disable the 'On-Demand' scanner and the scheduler. No anti-virus icon should appear in the tray or it will interfere with the anti-virus scanner in the mail server!).
  3. Enter the complete pathname of the file: f-prot.exe.
  4. Enter the scanner arguments: /AUTO /DISINF /DELETE /NOBOOT /NOMEM /SILENT %f
  5. Select 'Check Return Code' and enter the values: 3,6
  6. If you wish the recipient to receive notification of viruses, select 'Notify Recipient If Virus Found'.
  7. If you wish the sender to receive notification of viruses, select 'Notify Sender If Virus Found',
  8. Click 'Apply'.
  9. Exit and restart ISMail.

Note: F-Prot must be Registered and kept updated or failures will eventually occur.