6

I'm doing internet servers for like 30 years now. The last three years I went back into operations and working with all the new infrastructure wonders. Feels really great. From time to time I am doing work on our mailserver that is used as a relay for customer machines. The mail queue is always a place to have a look at for things going wrong with mails.

When checking on some of the destination domains that are currently not reachable, I see a lot of domains that have no MX records set at all. My knowledge is: if you want to be reliably reachable by mail add at least two MX records of mail servers that will be able to receive mail for that domain. One master and one fall back machine. Having no MX record at all the mail server will fall back to retrieving the IP Adress of the destination mail server via the A record of its domain.

The domains in question are from businesses that are real no spam hosts or such.

These sites are misconfigured. Roughly 15 years ago such configuration would be a sure pointer to an IT department running on windows without a clue about the internet.

Did I miss anything important changes in mail configuration or is the mail misconfiguration just on the rise?

  • I don't understand - you mean that these companies have no MX record at all? For my understanding this would mean that they cannot (or do not want to) receive emails at all. MX record is always needed if you want to receive mails for a domain. – Tobias Nov 19 at 11:00
  • 1
    Not all domains have or want mail, therefore don't need MX records - some may purely be for web traffic. A company may also have several domains, but only use one for mail. – Smock Nov 19 at 11:37
  • 3
    @Smock if they want no email, they should use a "no service MX" aka "null MX" tools.ietf.org/html/rfc7505 – Fabian Nov 19 at 12:19
  • 13
    @Tobias An MX record is not needed for receiving mail. Having no MX will result in a A record lookup for the given domain. – itsafire Nov 19 at 12:26
  • 1
    @Tobias the reason is probably that you only came into contact with properly configured domains and do it properly yourself. Actually it's ridiculous that a standard that was introduced in the 80s(!) is still omitted by some "administrators". Part of the reason at least here in Germany is the lack of properly trained IT-professionals; the market is dry but especially smaller companies don't want to pay wages that attract professionals. So they hire people with lackluster (if any) IT-education. And since they have no clue themselves they can't really assess the skill sets needed anyways. – Broco Nov 22 at 14:29
7

These sites are misconfigured. Roughly 15 years ago such configuration would be a sure pointer to an IT department running on windows without a clue about the internet.

This hasn't changed much. Many companies try to cheap out on the expenses for proper IT support and have a random employee with some basic understanding of IT manage their stuff and those people tend to think that they did everything right once they are able to send and receive emails in a testing environment. Those people might be able to follow an online howto on how to set up exchange or some other random mail server software but they lack the basic understanding of DNS, especially when it comes to reverse DNS lookups, MX records etc.

Did I miss anything important changes in mail configuration or is the mail misconfiguration just on the rise?

No, you didn't miss anything. The recent times have seen many out of the box solutions for all kinds of services and easy to use colorful UIs, including email servers which encouraged many (especially smaller) companies to cheap out on spending cash for external services and/or IT support. This caused and will keep causing multiple issues.

Some of our customers sent unencrypted emails without knowing it, some wondered why their emails don't reach certain mailservers but others work just fine (caused by DNS errors like missing MX records, lack of encryption etc.).

You don't necessarily need a fallback machine for a proper configuration, especially in smaller companies, but having no MX records at all will result in a lot of problems. So yes, you got that right.

  • Sad as it is. Just wanted this to be on the net :-) But for a resilient mail server setup I would definitely like to have a fall back mail server that is not in the same network as the primary one. – itsafire Nov 19 at 12:28
  • 1
    ……having no MX records at all will result in a lot of problems.” And may I know what problems you’re referring to? Please excuse my ignorance, but why is it that looking up A record instead is never enough? – Константин Ван Nov 23 at 1:55
  • 1
    @КонстантинВан for example because many Mailservers refuse to deliver mails to domains with missing MX records even though RFC says they should default to the A-record. Yahoo is one example. – Broco Dec 1 at 21:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.