I want to put a postfix test mailer on ubuntu, what to do with the domain if it does not exist?

Question

linux

Good day, I want to put a postfix test mailer on ubuntu, for self-development (in Linux it’s quite an initial level), the question is the following:
1) Will the mailer on ubunut be normal
2) are there test domains or sites (FREE) in order to register a domain name in the mail server
3) maybe someone will throw off a thread for a beginner in an understandable language for a step-by-step installation of a mailer (hands grow from the right place, but still there is sometimes a stupor in Unix systems since there is no one to help)

Answer 1

Where did I start:
1. interface31.ru/tech_it/2010/09/pochtovyj-server-st...
2. interface31.ru/tech_it/2010/10/pochtovyj-server-dl...
3. interface31.ru /tech_it/2013/10/pochtovyy-server-dl...
This is about theory.
But about what kind of mailer to install is a separate issue

Answer 2

1) It will become
2) You can find free domains (at least 5 years ago I found it), but in a year you still have to pay
3) Sorry, not for me.
Let me clarify on the second point. Most likely these domains will be 3 levels.
So the advice is to find a normal domain that suits you and pay for it. There are only about 100 rubles. And this is a year. Agree, not so much. And in the end it turns out to be useful enough :)

Answer 3

Free domain
www.freenom.com/en/index.html?lang=en

Answer 4

Spammer? Perhaps a beginner?
Why do you need a domain if most of the normal mail services will reject you or send you to spam? What sendmail did not please?
Read about PTR, DKIM.