E-mail Filtering

Filtering is a feature that enhances SMTP security within TFS Secure Messaging and safeguards against the unauthorized mailing of proprietary company information. e-mail can be filtered by sender, receiver, domain name. IP address, key words within the content of the e-mail text, attachment size, attachment type and mail flow.

Location Filter

You can select which mail servers and Internet domains you should accept e-mail from in this channel. You can also select mail servers or domains that you do NOT wish to accept e-mail from. Finally you can specify certain combinations of mail servers and domains so your TFS only will accept e-mail from a domain if the e-mail actually comes from a trusted mail server that you know is associated with that domain.

IP Filter

You can enter one or more IP addresses of mail servers that you either want the TFS SMTP Server to accept or deny e-mail from. If denied, the SMTP Server will give the SMTP response code "550 Access Denied".

Examples of Usage:

You want all your incoming e-mail to come from a remote machine at 128.64.32.16 and not accept e-mail from any other machine on the Internet

You are on an Intranet and only want to accept e-mails from machines on your local network, 192.168.1.0

You know that the mail server with the address 194.213.70.6 belongs to a domain full of pranksters that like to send you fake e-mails and you want it to stop.

Domain Filter

You can enter one or more Internet domains that you either want the TFS SMTP Server to accept or deny e-mail from. If denied, the SMTP Server will give the SMTP response code "550 Sender Rejected".

Examples of Usage:

You get fake e-mails from user@company.com have reason to believe that no one from that company would ever send you a real e-mail, you mant to block all incoming e-mails from that domain.

You have an Intranet setup and only wish to accept e-mail from other users in the acme.com domain.

Domain & IP Addresses

Combines domains and IP-addresses so that the TFS SMTP Server will only accept e-mail from a specified address if it comes from a listed and trusted mail server. You can list one or more trusted mail servers for each domain. Separate the domain name and IP number(s) with a space.

Example of Use:

You wish to make sure that e-mail from the domain acme.com actually comes from one of the two mail servers in that domain and stop anyone from another mail server from posing as an Acme employee.

Content Filter

Filtering by keyword content can prevent the sending or receiving of e-mail to specfic users and/or specific companies or the sending or receiving of e-mail that contains certain words. For easy organization, lists of key words can be created and stored within the Secure Messaging Server.

Example of Use:

You wish to make sure that e-mail is not being sent or received that contains any reference to any of a number of hate groups.

Attachment Filtering

Filtering by attachment size and type can prevent large or potentially dangerous attachments from being sent or received, such as .avi or .exe files. These files are usually large in size and slow down network processing by consuming bandwidth.

Example of Use:

You need to stop a disgruntled former employee from flooding your mail server with multiple large files and crashing your network.