At times, you might want to
identify a specific email address or an entire domain on the Internet
that is sending you messages that you either want to completely allow or
specifically deny the receipt of messages from that source location.
The content filtering function of Edge Transport Services enables you to
create a white list that always allows content to be received from a
user or domain, or specifically allows for the denial of messages from a
user or domain.
Do note that each user
can also allow and deny message communications, so the choice to allow
or deny content at the server level should take into consideration that
the communication is organization-wide and that making a setting at the
Edge Transport server level will have a positive impact on the
appropriate receipt of content to all users in the organization.
An example of a deny filter
on a user address or entire domain would include a situation where a
user or domain is sending inappropriate content to several users in the
organization. Rather than having each user make a configuration to block
content from a user or domain, it can be set at the server level.
Conversely, if
users in an organization want to receive all messages from a user or
domain, those names can be added to a white list that will always allow
messages to be received by users or the entire domain in the
organization.
Configuring the
Content Filter Agent to Allow (White List) Specific Senders, and Sending
Domains
The Exchange Management
Console allows you to exclude specific keywords, phrases, and
recipients within your organization from content filtering checks;
however, you can only exclude specific senders and sending domains from
content filtering through the use of the Exchange Management Shell’s Set-ContentFilterConfig
command, using the BypassedSenders and BypassedSenderDomains
parameters, respectively.
The BypassedSenders parameter
allows you to specify up to 100 external email addresses to exclude from
content filtering, with each entry separated by a comma:
Set-ContentFilterConfig –BypassedSenders [email protected], [email protected]
When excluding a
specific email address (for example, [email protected]), consider whether it is safe to exclude the domain
using the BypassSenderDomainscompanyabc.com). Not only does this save you time and message
retrieval because of false positives, it also consumes fewer entries in
your list, leveraging both lists and the allowed maximum of 100 more
efficiently. parameter instead (for example,
The BypassedSenderDomains parameter works similarly to the BypassedSenders parameter, allowing you to specify up to 100
external domains to exclude from content filtering, with each entry
separated by a comma:
Set-ContentFilterConfig –BypassedSenderDomains *.companyabc.com, company123.org
Note
Wildcard use is supported to designate the
exclusion of subdomains under the excluded domain—for example,
*.companyabc.com.
Configuring the
Content Filter’s SMTP Rejection Response
The SMTP Rejection
Response is inserted into a SMTP nondelivery report (NDR) that is sent
in reply to a rejected message. The default message is Message Rejected
Due to Content Restriction. This message can be changed using the Set-ContentFilterConfig
command with the -RejectionResponse
parameter. The SMTP Rejection Response cannot exceed 240 characters and
must be enclosed in quotation marks.
Note
The SMTP Rejection
Response cannot exceed 240 characters and must be enclosed in quotation
marks:
Set-ContentFilterConfig -RejectionResponse "Message rejected, an error has occurred. Contact your HelpDesk"
