Telling friends about Office 365 and its advantages I very often hear a question on how to assign to it custom domain. I have faced this problem itself when migrated to my own Office 365 account. Unfortunately, at that time there was no detailed documentation about an assigning custom domain with Office 365 account. Nevertheless, it would not be acceptable to use the standard domain. Therefore it was necessary to solve a question experimentally. It is probably that at present such section in the documentation have added.

So, that it is necessary for you to make the first – to register an account in Office 365. For this purpose we follow the link and select Free Trial. Basically, it is possible to buy an account, but if you select Trial mode it without problems can be transformed into a paid account later. After filling of all necessary fields we get possibility to use service in “.onmicrosoft.com” domain.

Step 1: domain verifying

Domain verifying is necessary to make sure, what exactly you are the owner of the domain. For check of your domain you will asked to add TXT test record (or MX – on your choice) in DNS of your domain.

To fulfill domain verifying, we should enter into a control panel of Office 365 account and to select "Add and verify your domain" link.

After entring of a domain name you will give contents of record which should be imported to domain settings, and also all steps for their performing.

We should add appropriate record in domain settings and to wait some time that they had time to be applied. After records in DNS were updated, the domain will appear in the list of Office 365 domains.

Step 2: choosing domain linking mode

Now it is necessary to select a domain linking mode.

By default, Office 365 will suggest to use his Name Servers for your domain (ns1.bdm.microsoftonline.com and ns2.bdm.microsoftonline.com in my case). If this variant suits you, we go to domain settings and change Name Servers to the offered. After that at you should earn all and any other actions on domain settings it is not necessary to fulfill.

Such variant didn't suit me, as it is convenient to me to use other server as Name Server . If to you too, read next.

Step 3: adding necessary record to domain settings

Для того, чтобы использовать собственный Name Server, но при этом пользоваться Office 365 нужно добавить несколько записей в настройки домена. Для этого переходим во вкладку “Domains” и выбираем “DNS Manager”.

DNS Manager contains settings for your domain. If you use offered in the second step Name Servers here you can control records for your domain. Now this information is useful to us for adding of appropriate records for the domain.

That it is necessary to make all – to add similar records for the domain.

After executing of these actions it is necessary to wait some time that settings had time to be applied. After that it is possible to use Office 365, but already with your own domain.

BTW, you can link your own domain in Trial mode too.

I wish successful domain linking!