Ideas to Improve Spam Blocking

Idea shared by kevind - 11/21/2017 at 8:59 AM

Under Consideration

With Black Friday right around the corner, we could use better spam blocking and filtering for SM 15 and 16. We've seen over 100,000 spam messages come in over the last 30 days!

Fortunately, we're able to classify them as spam and keep them out of the Inbox. But the server has to do a lot of work. If there were just a few more ways to block at the SMTP level, we'd be golden. Several great ideas to accomplish this are right here in the forum:

Add FCrDNS check (simple and effective)
Fix the null sender check so it blocks not just scores
Stop fake messages from local domain:
- from the user to themselves
- from other users (like the boss)
Block spoofs of popular domains
Validate from addresses to block phishing & malware

The first 2 bullets could probably be done in a day. And they don't all have to be completed. Just one of these enhancements would be a reason to give thanks this holiday. Happy Thanksgiving!

7 Replies

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kevind Replied

11/22/2017 at 9:40 AM

Is there a way to set up an External Spammer rule in Security Settings? It would work similar to an Internal Spammer rule, but in reverse.

For example, if SM receives >100 messages over a 10 minute period from an external IP, then either throttle that IP or block it for 30 minutes.

If this doesn't exist, it would be a nice feature.

Linda Pagillo Replied

11/24/2017 at 1:19 PM

Hi Kevin. Have you tried the Declude/Message Sniffer combo along with configuring a few reliable RBLs at the SM incoming connection checks level for anti-spam filtering? These 3 things are what 95% of our customers use and they are very very pleased with the results. If you would like to give it a try, let me know and I can explain how to get started. Thanks.

Linda Pagillo
Mail's Best Friend
Email: linda.pagillo@mailsbestfriend.com
Web: www.mailsbestfriend.com
Office: 703.988.3606

Authorized Reseller of SmarterTools Products
Authorized Reseller of Message Sniffer

kevind Replied

11/28/2017 at 10:22 AM

Thanks, Linda, for suggestion. It seems like we're doing an OK tagging messages as spam and moving to Junk Mail. But we'd like to take it one step further and block spam at the SMTP level. Can Declude/Message Sniffer help with that?

Some of the above suggestions like FCrDNS and a Null Sender block checkbox would help block during the SMTP transaction and save server resources (CPU and disk) by not processing thousands of spam messages.

Linda Pagillo Replied

11/28/2017 at 11:49 AM

Declude and Message Sniffer cannot help with SMTP connection level blocking unfortunately. However, there are a few very reliable RBLs that you can set up at the SMTP incoming connection level in SM. To name a few, Spamcop, SpamHaus Zen, GBUDb, etc...

kevind Replied

12/14/2017 at 8:47 AM

Hey, just wanted to keep this thread alive. First, let me emphasize that SmarterMail has great spam blocking and filtering capabilities. Just trying to take it up to excellent by adding a few tools such as:

Null Sender check -- cannot check the box under Block. It doesn't have a N/A next to it, so you should be able to check it.

Let's classify the above item as a bug (cannot check the box) so that it can be fixed in v15. I can post this in a separate 'problem' thread if necessary. Thanks so much!!!

kevind Replied

1/2/2018 at 12:40 PM

Happy New Year!

Just following up on this thread. Can a few of the bullets from the top post be implemented in 2018 to help us block spam?

Thanks,

Kevin

Curtis Kropar www.HawaiianHope.org Replied

1/12/2018 at 1:30 PM

Just FYI, I am looking to take this to even a level past SMTP

We are looking at moving to pfSense for our firewall. As i understand it, there is a way to script importing IP addresses to block.. So If we can get smarter mail to generate a list of IP addresses, or even write our own module to dig and export that list, then we can block the traffic at the firewall, and not even bother with SMTP. Basically avoid the middle man and get the results directly to the front door guard.

www.HawaiianHope.org - Providing technology services to non profit organizations, low income families, homeless shelters, clean and sober houses and prisoner reentry programs. Since 2015, We have refurbished over 11,000 Computers !

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