diff --git a/config/clamd.conf b/config/clamd.conf
index 4e2b9d8..cd360b8 100644
--- a/config/clamd.conf
+++ b/config/clamd.conf
@@ -41,6 +41,9 @@ ScanArchive yes
 ###############
 # Scan
 ###############
+# Close the connection when the data size limit is exceeded.
+# The value should match your MTA's limit for a maximum attachment size.
+StreamMaxLength 1024M
 
 MaxScanSize 1024M
 MaxFileSize 1024M