Symantec Mail Security, Administration Manual

Page: 106 / 258

106 Configuring email filtering
Managing policy resources
If you add Sender Authentication domains, it’s best to specify the highest level
domain possible, such as example.com, because subdomains of the specified
domain will also be tested for compliance.
Warning: Authenticating all domains can lead to significant unnecessary
processing load. Many domains do not publish an outbound email policy, or
publish only an informational policy. Attempting authentication on these
domains does not lead to any action, and will use processing resources, at times
excessively. Authentication is most effective for domains that publish hard
policies that are frequently spoofed in phishing attacks.
To enable sender authentication
1 In the Control Center, click Policies > Sender Authentication .
2 Check Enable Sender Authentication .
3 Under Authentication Types, check Sender Policy Framework (SPF) , Sender
ID , or both.
4 To choose domains to authenticate, click Authenticate only the following
domains , or to authenticate all domains, skip to step 6.
5 Click Add , type a domain name, and click Save to add domains to the list.
Optionally, you can click on a domain or check the domain and click Edit to
edit the spelling of a domain you already added. You can also check a domain
and click
Delete to delete that entry from the list.
6 Click Authenticate all domains to attempt sender authentication on
incoming messages from all domains.
7 If desired, change the default action, or add additional actions.
By default, each failed message has the phrase [sender auth failure]
prepended to its subject line.
8 Click Save .
Managing policy resources
The settings under Policy Resources are used in the conditions or actions for
policies.
Annotating messages
Annotations are phrases or paragraphs that are placed at the beginning or end
of the body of an email message when you choose the action Add annotation. An