Chimera Computing Ltd

EFS - Helping Deal with Spam



By default, EFS will extract email addresses from the message headers and deliver to all email addresses for your primary and secondary domains. If you find you receive too many junk emails (caused by email sent to non-existant email addresses in your domain and ending up in the postmasters mailbox) you can force EFS to use a specific list of known valid email addresses. To do this, create an EFSUSERS.TXT file in the same folder as the EFS executable. Add every fully qualified email address in your domain, one per line to the file and save it. Quit EFS then re-launch it. The log screen will indicate that the EFSUSERS.TXT file has been detected and will now only send to email addresses that match to entries in this file. For example:

  • Your primary domain is ""
  • You have 5 staff members, Joe, Sue, Bob, Fred and George
  • You also have a distribution list called Staff

    You would create an EFSUSERS.TXT file in the EFS folder that contains the following:

    EFS will open and read the file each time it checks for email therefore, you can dynamically update this file without having to restart EFS.

    Tip: If you are running Microsoft Active Directory with Exchange 2000 or 2003, click here to download a VBScript that will enumerate all email addresses in your domain and create an EFSUSERS.TXT file automatically for you. Save the VBScript to the C:\Program Files\E.F.S\ folder, open a command prompt and type cscript efsemail.vbs Consider creating a scheduled task in Windows to execute this script on a regular basis to keep the EFSUSERS.TXT file up-to-date.

    By default, as each inbound message is written into the EFS Inbox folder, an internal validation process is run to check that the message retrieved via Pop3 was written to file - ie: that the actual message file exists. If the message file does not exist as it should, the message is unmarked from deletion from the Pop3 server. This is simply a safety precaution to help ensure email messages are not lost due to disk corruption or similar type of issues (albeit, in very rare circumstances).

    The downside of this is if you have realtime antivirus/antispam software installed and it is set to block access too or delete the message file, then EFS detects the file is missing and unmarks the message from deletion - therefore it will sit on the Pop3 server indefinately. To get around this, under the EFS 'Control' tab, tick the following boxes:

    Realtime Antivirus Installed (disables message file write checking)
    Delay SMTP Sending to Allow Realtime Anti-Virus Scanning

    Leave the default seconds as they are initially - these allow the realtime antivirus/antispam software some time to scan the entire message. You can adjust later if necessary.

    NOTE: Since different vendors of antivirus software work differently, we cannot guarantee that the above methods will stop all viruses or spam.

    (Chimera Computing Ltd)