You are sending a message with a large number of recipients through brightmail gateway for outbound filtering. You then notice inbound mail is getting delayed for a period if time.
This can happen when there is only one scanner that handles both inbound and outbound traffic. If this message is caught as spam due to the high amount of recipients, or if the the message recipients belong to multiple domains, the delivery queue can get filled with a lot of mail traffic trying to get to either quarantine or external locations. This will effect inbound emails such that the software will not be able to deliver them in a timely manner.
If it is required that certain outgoing messages contain a high amount of recipients, there are two potential solutions that may remedy this problem.
1. Set up a dedicated scanner for outbound traffic.
2. Restrict the number of recipients allowed on outbound messages by doing the following.
Log into the Brightmail Gateway Control Center with the Admin account.
Click Configuration under 'hosts' on the left side-bar.
Edit the scanner that is experiencing the symptoms.
Click the SMTPtab.
Click Advanced Settings.
Click the Outboundtab.
Change the number under 'Maximum number of recipients per message' to something lower than 1024.
Imported Document ID: TECH148503
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