It takes between 2 to 12 hours to propagate all over the major DNS.
DNS record types define the information stored in a DNS record, such as an IP address, mail server information, or other data associated with a domain name. Common types include A, AAAA, CNAME, MX, NS, TXT, PTR, SOA, SRV, and CAA.
A (Address): Maps a domain name to an IPv4 address.
AAAA (IPv6 Address): Maps a domain name to an IPv6 address.
CNAME (Canonical Name): Creates an alias for a domain name, pointing it to another domain.
MX (Mail Exchange): Specifies mail servers responsible for accepting emails for a domain.
NS (Name Server): Indicates the authoritative name servers for a domain.
TXT (Text): Stores text data, often used for domain verification, SPF records, or other administrative information.
PTR (Pointer): Used for reverse DNS lookups, mapping an IP address to a domain name.
SOA (Start of Authority): Contains administrative information about a domain, such as the primary name server, contact information, and refresh intervals.
SRV (Service): Specifies the location of services like SIP or LDAP servers, including the port number.
CAA (Certification Authority Authorization): Specifies which certificate authorities are allowed to issue certificates for a domain.
SPF (Sender Policy Framework): Used to prevent email spoofing by specifying which mail servers are authorized to send emails for a domain (often implemented using TXT records).
DMARC (Domain-based Message Authentication, Reporting & Conformance): A protocol built on top of SPF and DKIM to define how email receivers should handle messages that fail authentication checks (also often implemented using TXT records).
DKIM (DomainKeys Identified Mail): A method for email authentication that uses digital signatures to verify the sender's identity.
It's amazing how many entities don't have proper DMARC records these days. For example, GE doesn't have a policy set. I have to deal with them on a professional level, and their mails are always getting trapped because they suck.
I've had to bitch at a few large corp entities about their non-compliant SPF records as well.
I don't think anyone cares anymore. Most of the admins are DEI anyways.
You are correct, they don't care. Although I did get one large airline to fix their crap and they now have a properly formed SPF that doesn't violate rules put into place in 2014...
Holy fuck that's embarrassing for such a large company. Setting up DMARC isn't even that hard.
When I respond to people complaining about DMARC holds I always make sure to tell them it's because the sender has bad IT policies and practices.
It is. They went so far as to HAVE the record, but nothing as to what their mailserver should do when it encounters a bad mail. Japan is really bad about this too - they're high tech, but it's like they went full stop in certain areas. We get a lot of spam from that part of the world because their mailservers are wide open.
I always check using mxtoolbox and tell complainers exactly why their mail got stopped, or why they got the spam.