Block Authentication by Country - Server Global

Problem reported by Hilton Cesar Feitosa Milanez - 1/7/2026 at 5:54 PM

Submitted

Hello SmarterTools,

Add a new feature using Block Authentication by Country to create an IDS Block rule to allow or disallow receiving emails from specific countries. Advantages:

1. Reduced spam, which would be great.

2. Reduced DDoS attacks.

3. Reduced password brute-force attacks.

4. Reduced SMTP Sessions (Harvesting).

7 Replies

Reply to Thread

Mark Johnson Replied

1/7/2026 at 8:21 PM

what countries would you block?

Hilton Cesar Feitosa Milanez Replied

1/7/2026 at 8:48 PM

Hello Mark Johnson,

Thank you for your attention and feedback, here it is:

Afghanistan

Pakistan

Turkmenistan

Tajikistan

Iran

Uzbekistan

Kazakhstan

Kyrgyzstan

Indonesia

Taiwan

Hong Kong

North Korea

Singapore

Russia

Kuwait

Croatia

Bosnia and Herzegovina

Belarus

Ukraine

Iraq
Armenia

The list is likely to be longer, but these would be the main ones.

Mark Johnson Replied

1/7/2026 at 9:52 PM

you can block auth attempts by country now .. do you have that setup?

we only allow logins from Australia, for customers travelling we add/remove countries by request

this has reduced alot of activity

how would you handle any complaints about legit emails to your users from any country you block?

Hilton Cesar Feitosa Milanez Replied

1/8/2026 at 5:46 AM

Hello Mark Johnson,

Block Authentication by Country is currently configured only for Brazil. I sent this suggestion to apply it as a rule to avoid receiving emails from certain countries, such as those I mentioned.

I don't want to receive any emails from the list I sent; in other words, I want to block the connection. Our clients don't do business with clients from these countries.

Applying Block Authentication by Country as a feature to avoid receiving emails from these countries would be great; it's just a suggested feature.

Mark Johnson Replied

1/8/2026 at 3:12 PM

yep understand, our customer base is a bit more expanded so would be tricky ..

other issue is that most of our latest phishing emails are coming via the USA!

info here:

Attack analsyis: Free gift of AAA emergency kit - SmarterTools

its an ongoing challenge for anyone hosting email services, good luck to us all!

Hilton Cesar Feitosa Milanez Replied

1/8/2026 at 3:50 PM

Hello Maek,

I found a way to drastically reduce the use of blacklists. I sampled about 200 spam emails received by looking up the IP address in MXTOOLBOX.

I studied how blacklists work, adjusted the configuration of all of them, and also found some that weren't filtering because I hadn't configured them properly.

I'm using 38 blacklists now; I still get some spam, but very little. I managed to reduce it by 95%.

Curtis Kropar www.HawaiianHope.org Replied

1/12/2026 at 12:48 PM

HI Hilton.

You cab do full country blocking with a firewall. That is what we do. pfSense is a free firewall and you can install a "package" (pfBlockerNG) as an add on (also free) and block all kinds of stuff. Known spammers, known hacker IP's, countries and even full continents. You will need to sign up for a free account with Max Mind.

In the pfBlocker "IP" settings you will see : "MaxMind GeoIP configuration:"

"GeoIP database GeoLite2 distributed under the Creative Commons Attribution-ShareAlike 4.0 International License by: MaxMind Inc. The GeoIP database is automatically updated each day at a random hour.
To utilize the free MaxMind GeoLite2 GeoIP functionality, you must first register for a free MaxMind user account. "

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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