What is the performance impact on Symantec Mail Gateway (SMG) mail-flow when using large static sender lists (bad or good)?
For example; Adding 10000 IP addresses to the BAD sender list.
Release : 10.7.x
Component : SMG
The performance impact of using large sender lists is uncertain as there has not been any rigorous performance testing in this area. While we do not have a hard and fast rule regarding "how many of X can I add to SMG before I start seeing negative effects", all lists and filters will slow mail-flow so it is recommended that lists are kept to a minimum and maintained regularly.
Other suggestions on how you could manage large numbers of IPs for either good or bad senders are:
Build up a local DNS Block or Allow server. This option would be scalable and would allow administrators to fully manage as many IPs needed.
If proceeding with adding IP addresses defined as good\bad senders, consider using ranges if possible rather than individual IP addresses.