How to strictly reject email without MX

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smileluo

Member
Jan 16, 2021
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reject_unknown_sender_domain
Will reject email if mail from domain has neither mx record nor a record,for some spammer,they will sending forged emails that has A record but no MX record,in that case,if the IP is clean,postfix is accepted by default.
If there any way to direct block those without MX record?
 
To reject email when the HELO/EHLO hostname has neither DNS A record nor MX record, use

reject_unknown_helo_hostname
 
The spammer will use HELO that has A record,so reject_unknown_helo_hostname not working to block it
 
Add the following lines in smtpd_sender_restrictions. It will reject email if the domain name of the address supplied with the MAIL FROM command has neither MX record nor A record.

Code: 
smtpd_sender_restrictions =
   permit_mynetworks
   reject_unknown_sender_domain
   reject_unknown_reverse_client_hostname
   reject_unknown_client_hostname
 
smileluo said:
reject_unknown_sender_domain
Will reject email if mail from domain has neither mx record nor a record,for some spammer,they will sending forged emails that has A record but no MX record,in that case,if the IP is clean,postfix is accepted by default.
If there any way to direct block those without MX record?
Click to expand...
Not that I know of - also I would not do that - having a domain without MX record sending mail is not uncommon (and perfectly fine according to the relevant RFCs)

I hope this helps!
 
As found some spammers use this method to sending spams. Most of case,the envelope from without MX is spams!
 
I am thinking a method to block all of such and make a list to whitelist some,if really good company without MX
 
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