Anti-spam protection is based on the CloudMark and SpamAssassin filtering software that, besides checking against real-time black lists, uses a sophisticated analysis of message header and text to assign a weight to each message. This weight is called a spam score. A higher spam score indicates a higher chance that the message is spam. When the assigned weight exceeds a certain threshold, the filter routes such messages to the Junk Email folder or permanently deletes it, unless the sender is on the white list (Safe Senders list) either for the account or for the individual mailbox.
The following checks are always performed:
- Check against RBLs (Real-time Black Lists) provided by Cloudmark and Invaluement.com
- Check for empty FROM field in Headers
- Check for a valid fully-qualified senders (FROM) email address
- Check for a valid domain in the FROM address (check for a valid A or MX record)
If an email message does not pass one of these checks, it is not accepted by the mail servers for delivery to recipients.
Mail is filtered using default Advanced Email Security settings:
- spam score of 3 is used as a threshold for marking email as spam
- spam score of 20 is used as a threshold for deleting email
- messages with viruses and dangerous attachments are rejected
Advanced Email Security performs checks against the following RBL's to increase the SPAM score of the message:
Note: the availability of the settings below depends on your plan.
- You can adjust spam sensitivity levels by sliding the handles:
- determine when emails are delivered to the inbox and when they are sent to the junk mail folder
- enforce kill level to decrease amount of messages going to junk
- or, do the opposite and disable kill level to ensure no messages get deleted right away
- Create and manage account wide safe and blocked lists
- Overwrite default settings for delivery of attachments
If an email address or domain is on the account Blocked Senders list, any email from a sender that matches will be discarded, independently of the account-wide settings below.
If an email address or domain is on the Safe Senders list, then any mail from that sender will be delivered to the mailbox of the recipient, regardless of the spam score.
Mailbox-level lists always take precedence over account-wide lists.
Note: DNSBL checks are performed during the SMTP transaction and rejected prior to the DATA command. The mail is rejected before the message is received; therefore, mail from sending mailservers whose IPs are on one of the DNSBLs used by Smarsh Hosted Services will be rejected even if they are on the account-wide Safe Senders list. There is NO work around or fix for this, other than for the sender to have their IP address removed from the listing DNSBL.
Working with account-wide Safe Senders and Blocked Senders lists
Note: this feature availability depends on your plan.
Click Safe & Blocked Lists to view and manage the account-wide Safe Senders and Blocked Senders lists.
- To filter addresses, you can enter the beginning letters in the search box, select the type to show (All Types, Email, or Domains), and click the Apply Filter button.
- To remove an email address from its respective list, check the box next to that address (or addresses), then click Delete.
- To export the current Safe Senders or Blocked Senders lists to a file, click the Export List to CSV File button on the appropriate tab.
Adding a new address to the Safe Senders or Blocked Senders list
To add new addresses or domains to a list, open the tab for the list you want to add to. Enter the email address or domain in the box, then click Add. If you add a domain to a list, it causes mail from ALL USERS at that domain to be treated as safe or blocked.
- The format for email addresses must be firstname.lastname@example.org.
- The format for domains must be @domain.com.
- Wildcards (* or ?) are not allowed in the Blocked or Safe Senders lists (for example, you can't use @*.tld or @domain??.tld).
Accept messages with dangerous attachments - Read the Knowledge Base article on Why do messages with attachments get rejected by the Exchange Server content filter? for a list of prohibited attachments.
- Safe Senders Only - Messages with dangerous attachments will be delivered only if the sender's address is on the Safe Senders list.
- Everyone - Messages with attachments are not restricted.
Changes to these settings will not take effect until you click Save Changes.
Mail considered to be spam will be placed in your Junk E-mail folder in either Outlook or Entourage. In addition, Outlook users can take advantage of the built-in Junk E-mail features:
- Outlook 2003/2007 > Actions > Junk E-mai
- Outlook 2010/2013/2016 > Home > Junk
- Outlook 2011/Entourage > Home > Junk
For more information on Junk E-mail settings, please refer to the following Microsoft article About the Junk E-mail Filter.
Note: Outlook may produce the following error when you are working with the Junk E-mail settings:
Although the warning states that you must be in cached mode for the settings to work, our servers will allow these settings to be changed without requiring the user to be in Cached Exchange Mode. You can ignore this error.