Figure 1: Enable AntiSpamAgent feature
After restarting the Exchange Transport Service, we have a new tab in the Exchange Management Console as shown in the following image:
Note:
We will examine more closely each of these anti-spam features:
Internal content filtering (Content Filtering)
The Content Filter agents work with spam reliability rating (SCL for short). This rating is one of the numbers 0 - 9 for each message; A high SCL level means it is more like spam. You can configure this agent according to the message rating as follows:
You can also customize this filter yourself and configure exceptions if you want.
Allowable IP List (IP Allow List)
With this feature you can configure certain IP addresses that are allowed to connect to your Exchange server. So if you have a dedicated mail forwarding server in your DMZ, you can add its IP addresses so that your server will not accept connections from other servers.
List of providers with IP permission
In general, you cannot configure your own IP-enabled lists without encountering any errors that can lead to problems receiving emails from your customers or other business partners. Therefore, you should contact a public IP that allows listing providers that work with you. This means that you will have better quality in this service and besides that is higher business value.
IP list is locked
This feature allows you to configure IP addresses so that these addresses are not allowed to connect to the server. In contrast to the allowed IP list, this feature provides a black list, not a white list.
List of providers with IP locked
This feature is similar to the blacklist of providers. Their task is to publish lists from servers or IP addresses that are currently spam.
Recipient Filtering (Recipient Filtering)
If you need to block emails to internal users or domains, this feature is one of the things needed to do that. You can configure this feature and then add the appropriate addresses or SMTP domains to your blacklist. Another interesting feature is that it allows you to set up a profile that will only allow you to accept emails from recipients on your global address list.
Sender filtering (Sender Filtering)
If you need to block certain domains or external email addresses, you will have to use this feature. With this feature, you can configure a blacklist of addresses of senders and domains that you will accept.
Sender ID (Sender ID)
Sender ID agent relies on the header of the simple mail transfer protocol multiplied - RECEIVED Simple Mail Transfer Protocol (SMTP) and a query for the domain name system (DNS) service of the system being sent to determine the action takes place on a notification sent. This feature is quite new and based on the needs of a specific DNS setting.
Sender ID is intended to combat the personalization of senders and domains (or problems can be called spoofing). A spoofed email is an email message whose address has been changed to appear as if it was sent from another sender. These spoofed mail often contain the FROM in the header of the message to confirm originating from a dedicated organization.
The Sender ID evaluation process will generate a Sender ID status for each notification. The Sender ID status will be used to evaluate the SCL rating for that message. This status may receive one of the following settings:
Sender ID's status will be added to the email metadata section and then transferred to the MAPI attribute. The Junk E-mail filter in Microsoft Office Outlook will use the MAPI attribute during the SCL value creation process.
You can configure this feature to perform the following actions:
Reputation of the sender
The sender's reputation is one of the new anti-spam features in Exchange Server 2007 that is intended to block notifications based on many features.
The sender's reputation level calculation is based on the following information:
The sender's reputation will be in each of these statistics and give an SRL for each sender. SRL is a number between 0 and 9. You can configure what to do with the message in one of the following ways:
Conclude
As you can see after reading this introduction, Exchange Server 2007 provides a lot of features to increase spam protection on Exchange Server. If you do not use a dedicated Exchange Edge Server, you can add this feature to Exchange Server 2007 Hub Transport as described in the article. If you define a configuration for your specific server design, then you will have to add third-party software to meet your business needs.
If in case you need to have more than the functions described above, we recommend using Microsoft ForeFront Security for Exchange Server servers.