Sign In with your
Trend Micro Account
Need Help?
Need More Help?

Create a technical support case if you need further support.

"Reject unknown IP address" option does not work in InterScan Messaging Security Virtual Appliance (IMSVA)

    • Updated:
    • 14 Sep 2015
    • Product/Version:
    • InterScan Messaging Security Virtual Appliance 8.2
    • InterScan Messaging Security Virtual Appliance 8.5
    • InterScan Messaging Security Virtual Appliance 9.0
    • Platform:
    • N/A N/A
Summary
You noticed that IMSVA accepts emails from fake domains. For example, you receive an email from test@nonexisting.domain.com, wherein nonexisting.domain.com is not a real domain.
You enabled the Reject unknown IP address option to reject the email from the domain which does not match the reverse DNS. However, you can still receive the email even when this option is enabled.
Details
Public
When the Reject unknown IP address option is enabled, IMSVA only checks the PTR record of the sender's IP address, not the sender's domain in the Mail From command.
If IMSVA declines the sender domain's MX record with no IP address of the upstream MTA, many emails can be falsely rejected. Below are some of the reasons:
  • Many companies have multiple IP addresses. To split the traffic to different servers and lines, they use IP 1 is for sending emails while IP 2 is for receiving. Therefore, the company's domain MX record does not contain IP 1.
  • Some companies use mail service from a third party, which separates the inbound and outbound mail MTAs. Outbound MTAs do not accept any inbound mail, thus, clients cannot add outbound MTAs to their MX record.
The Reject unknown IP address option on the WebUI corresponds to the "reject_unknown_reverse_client_hostname" parameter in Postfix. For more details about this, refer to the Postfix article: Postfix Configuration Parameters.
Premium
Internal
Rating:
Category:
Configure; Troubleshoot
Solution Id:
1102287
Feedback
Did this article help you?

Thank you for your feedback!

To help us improve the quality of this article, please leave your email here so we can clarify further your feedback, if neccessary:
We will not send you spam or share your email address.

*This form is automated system. General questions, technical, sales, and product-related issues submitted through this form will not be answered.

If you need additional help, you may try to contact the support team. Contact Support


To help us improve the quality of this article, please leave your email here so we can clarify further your feedback, if neccessary:
We will not send you spam or share your email address.

*This form is automated system. General questions, technical, sales, and product-related issues submitted through this form will not be answered.


Need More Help?

Create a technical support case if you need further support.