What is the practical maximum number of SMTP blacklistings in SmarterMail V14?
Question asked by Lyle Hancock - 6/23/2015 at 1:40 PM
Question… How many black listed IP address can SmarterMail handle before it hits a list limit or compromises performance? 

I realize part of the answer is “hardware performance.” We’re running on a dedicated HP Proliant 8 core server with 32 GB of memory - plenty of performance. So the question is directed more at SmarterMail’s practical limitations.
Background… We use a spam filtering / security app that filters spam, monitors failed logins, detects various types of hacks and attacks and takes countermeasure by blacklisting the involved IP addresses in SmarterMail’s domain level blacklist via web services.
We recently encountered two coordinated brute force attacks. Collectively, the two attacks resulted in over 1,500 IP addresses being added to the SMTP blacklist. I’m concerned that 1,500+ might be close to or greater than the practical design limit for the blacklist. We're running the latest stable build of SmarterMail Version 14.

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Scarab Replied
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I've always worried about this myself and would like to know if there is a hard-limit as well.
However, I can assure you that if there is one you are far from it. We have over 6000 IP Blocks on our Blacklist in Smartermail and another 2000 SMTP Block Senders and Smartermail runs just fine (although it can be slow when making changes to any of the Security screens).
(And one of our tertiary Smartermail Incoming Gateways has only 1GB of RAM and a Celeron processor, if that tells you anything...although that one is only running v13.)
Lyle Hancock Replied
Thank you, Scarab. It's good to have some relative numbers to have a comparison.

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