Why is email blocked by the filter


This article applies to:

  • R3000
  • WF/WFR

Question:

  • Why is my email blocked by the filter? ii it a port block?

Reply:

The reason for the block is not the port but the SSL communication in the packet. The filter tries to get a certificate on all destination domains. The filter will block most SSL traffic when a certificate cannot be matched ip/domain on the smtp ' Helo' to the destination server. We are working to make this more flexible on certificate lookups.

Although this can sometimes lead to overblocking, being port-agnostic is actually one of the advantages of the Web Filter, in that it’s not just looking at the well-known HTTP ports.  There’s nothing to prevent a web server from listening on any port, but many web filtering solutions just monitor a few specific ports.  If the customer encounters issues in this area, they can use the Range To Detect to make the necessary exclusions. 

The range to detect is in Policy>Global Group>Range to detect.

add your Source ip and then go to source exclude and add your server ip's there.

Notes:


Last Modified 2/13/2012.
https://support.trustwave.com/kb/KnowledgebaseArticle14315.aspx