Easy! IT | Server | TXT Record

Everything might be not exactly correct in this article but it’s very useful for beginners to understand IT terms. If you want to learn IT but you don’t have any experience to work in the IT industry, I wish it helps you to understand IT and you like to study IT more.

Let’s start our 3 minutes lesson!

What is a TXT record?

TXT records are written in a zone file.
TXT records used to be written comments for only humans.
TXT records are now possible to put some machine-readable data.
TXT records are used for an email spam prevention and so on.

I suggest you read the following articles before you read this article if you don’t know DNS well.

DNS: IT Learning | Network | DNS | Japan Teams

Secondary DNS: IT Learning | Server | Secondary DNS | Japan Teams

1. TXT records used to be for human’s memo

A TXT record is one of the contents in a zone file and written texts(comments). A TXT record is used to provide the ability to associate freestyle text with a host or other names, such as human-readable information about a server, network, a data center, or other accounting information. However, now it is also possible to put some machine-readable data into TXT records.

2. There are two DNS roles

There are two DNS servers. One is an Authoritative name server. Another is called Caching DNS Server. Laptops usually ask Mr Caching DNS server the first question. If Mr Caching DNS server can’t answer the question, he will ask Ms Authoritative name server.

Mr **Caching asks Ms Authoritative when he doesn’t have a target in his cheat sheet.**

When Ms Authoritative receives the question from Mr Caching, she checks her job handbook called “Zone file”. There is much information in a zone file, and one of the information is a “TXT record”.

What is a “Zone file”?: IT Learning | Server | Zone file | Japan Teams

**What is an Authoritative DNS?IT Learning | Server | Authoritative name server | Japan Teams**

3. How to write “TXT record”?

You can actually write anything which you want in a TXT record. I’m writing for what this record is used for later. Firstly, I explain how to write “TXT record”. The format of TXT records is

“Domain name” IN TXT “Comments”

Thus, for example of “TXT record” is

big.meat.com. IN TXT “I wanna eat a lot of meat!!!”

Maybe you wonder why this record is needed. TXT records were traditionally used for a variety of non-standardised uses, such as a full company or organisation name, or the address of a host, and so on. Then now how are they used?

4. For what TXT records are used?

I’m explaining when you use TXT records. For example, you can write the organization’s name.

meat.com. IN TXT “This domain name is reserved for use by Meat corporation”

What’s more, you can use TXT records for security measures, such as SPF records, DKIM records, and DMARC records as well. I will explain the details on them in other articles. So I just write a simple summary about SPF here.

SPF records show you that “This mail server sends you! Other mail servers are con servers!”. For example,

IN TXT “v=spf1 ip4:192.168.0.1 ~all”

This is a sample of TXT records. In this case, the server whose IP address “192.168.0.1” is a correct sender! Other servers which have different IP addresses are fake! Though you have to do many other things to check if that mail is secured authenticity. This record is called an SPF record, but SPF records are actually one of TXT records!

If you need more details, I suggest you check the following articles too.

What is a DNS TXT record? | Cloudflare, TXT record – Wikipedia, TXTレコード（text record）とは – IT用語辞典 e-Words

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