Receiving tons of spamming emails every day

Operating System & Version
CENTOS 7.7
cPanel & WHM Version
v86.0.4

ImperialTrader

Well-Known Member
Aug 31, 2014
174
20
68
Egypt
cPanel Access Level
Root Administrator
Every day I receive tons of spamming emails.
It doesn't reach my inbox because some times, the sender IP is on the blacklists and other times, they are sending to a not existing email address.
But I receive more than 1000 spamming emails in 1 second only, is it could make a load on my server and could lead my server to fall down?
 

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keat63

Well-Known Member
Nov 20, 2014
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Welcome to my world.

If your'e lucky, then you might find a pattern in the sending IP's maybe a subnet or a few subnets, which you could then firewall.
If you could narrow these down to a specific country, then you could block that whole country in CSF firewall for a period until it subsides.

Do you have any custom RBL's configured in exim config. ?

I use the ones as per my image, whilst they are not fool proof, they do work well together.
I guess adding a few extra RBL's might help.
 

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ImperialTrader

Well-Known Member
Aug 31, 2014
174
20
68
Egypt
cPanel Access Level
Root Administrator
Welcome to my world.

If your'e lucky, then you might find a pattern in the sending IP's maybe a subnet or a few subnets, which you could then firewall.
If you could narrow these down to a specific country, then you could block that whole country in CSF firewall for a period until it subsides.

Do you have any custom RBL's configured in exim config. ?

I use the ones as per my image, whilst they are not fool proof, they do work well together.
I guess adding a few extra RBL's might help.
Ok, fine.

What if I didn't block them? Is that harmful to my server?
 

keat63

Well-Known Member
Nov 20, 2014
1,913
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Thats a good question, and one which I can't personally answer.
However, I know how annoying these can be and I'd be putting all sorts of obsticles in thier way to stop or slow them down.
 

cPanelLauren

Product Owner
Staff member
Nov 14, 2017
13,296
1,272
313
Houston
Excessive inbound email can cause some load, exim has to process the message, if you use SpamAsassin it'd have to scan the email, dovecot would have to process delivery. Each mail delivery can have 1000's of actions that need to be run though usually extremely fast and short lived.
 
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Matt.R

Member
Nov 18, 2018
14
5
3
United Kingdom
cPanel Access Level
Root Administrator
We've started to use the option in cPanel to "Filter Incoming Emails by Domain" (located in Email section). Did this because many emails were coming from domains like .best icu etc. We know for a fact that none of our genuine emails would come from such doamins so we simply blocked them. This actually works really well. This could also be used in conjunction with the "Filter Incoming Emails by Country" btw.