Rules

The procedure for editing an SMTP filter profile is as follows:

Select a profile from the list of URL filter profiles.

The table of filters will then appear as well as a screen indicating errors.

Possible operations

The available buttons are:

Add Inserts a line to be configured after the selected line.
Delete Deletes the selected line.
Move up Places the selected line before the line just above it.
Move down Places the selected line after the line just below it.
Cut Removes the selected line and moves it to the clipboard.
Copy Copies the selected line and moves it to the clipboard.
Paste Pastes the line from the clipboard above the selected line.

The table

The table contains the following columns:

Status

Status of the rule:

 

If Enabled, the rule is used for filtering.

If Disabled, the rule is not used for filtering. If this rule is disabled, the line will be grayed out in order to reflect this.

REMARK

The firewall will assess rules in their order of appearance on the screen: one by one from the top down. As soon as it comes across a rule that corresponds to the request, it will perform the specified action and stop there. This means that if the action specified in the rule corresponds to Block, all rules below it will also be set to Block.

Action

Allows specifying the result of the rule: Pass to allow sending and receiving e-mails, Block to prohibit them

Sender

Defines the sender of the e-mail. The value “none” can be selected as a sender.

Recipient (to, cc, cci)

Defines the intended recipient of the e-mail.

Comments

Comments relating to the rule.

An e-mail mask may contain the following syntax:

  • *: replaces a character string.

Example

*@company.com allows defining all e-mails from the internet domain of the company called COMPANY.

 

The following can also be seen:

  • ? Replaces a character.
  • <none>: This value can only be obtained when the Sender field is empty, and is used only for mailer daemons. When an e-mail cannot find its recipient on a remote mail server, the remote mail server will send back an error message, indicating that there is an error regarding the recipient. In this case, the Sender field in this error message will be empty.

A rule with the action “Block” can be created to prevent the e-mail from being sent if the sender is unknown.

Errors found in the SMTP filter policy

The screen for editing SMTP filter rules on the firewall has a rule compliance and coherence analyzer which warns the administrator when a rule inhibits another rule or if there is an error in a rule.

This analyzer shows rule creation errors and coherence errors.

Errors are displayed in the form of a list. By clicking on an error, the rule concerned will automatically be selected.