Plesk-Support answered my questions, here to share information with you:
#1
What are local SPF rules and what are their implications?
SPF fights return-path address forgery and makes it easier to identify spoofs.
The rules are set in the DNS records and you decide how you would like to setup them.
Let me show you couple of examples:
example.com IN TXT "v=spf1 mx -all"
This mean that mail from
[email protected] can be sent only from his MX record. There can be used other options. If other servers send mail from domain.com, you can describe them by giving "arguments" to the
a:, mx:, ip4:, and ptr: mechanisms.
mx: takes domain names and approves all the MX servers of these domains.
Example:
"v=spf1 a mx a:example.com -all"
Mail can be sent from his MX and from example.comserver.
You can find more information in the following article. Also, you can found a link to record generator there:
What is the SPF? How to configure and use SPF on Plesk server?
The behavior of SPF, therefore, the implications of rules, can be set in
Tools&Settings - Mail server settings - SPF checking mode. You can find a thorough description of the modes here:
https://docs.plesk.com/en-US/onyx/administrator-guide/mail/antispam-tools/sender-policy-framework-system-linux.59435/
#2
What are SPF estimation rules and how do they work?
If this questions wasn't answered in the first section, please, let me know what exactly do you mean by "estimation rules". If you would like to know more about SPF mechanisms, I can suggest to take a look to its RFC:
RFC 4408 - Sender Policy Framework (SPF) for Authorizing Use of Domains in E-Mail, Version 1
#3
How does Plesk check AAAA-Records and how does it process them?
It depends of the type of ip being set. When
<ip> is an IPv4 address, A records are fetched, when <ip> is an IPv6
address, AAAA records are fetched.
The rules for ipv6 addresses can be set in the DNS TXT records as well as rules for both types of ip. Let me share an example with you:
"v=spf1 ip4:XX.XX.XX.XX ip6:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX ~all"