Among Tumblr's customization options for your blog, one of which being the ability for your visitors to access it using a custom domain or subdomain instead of the standard Tumblr.com address. Setting up a new subdomain and associating it with your Tumblr blog requires you to add a new canonical name record to your domain name's domain name server records and to edit your Tumblr settings.
Log in to your account for your DNS provider. Open the domain name servers management page and add a new DNS record. Select CNAME as the record type, enter the subdomain you wish to use in the Host field and domains.tumblr.com in the Answers field. Save your new settings.
For some providers, you may have to use a Value record or something similar instead of Answers.
Log in to your Tumblr account and click the Account icon to open a new menu. Select **Settings."
Select the appropriate blog.
Click the Pencil icon to reveal the Use a Custom Domain option.
Select Use a Custom Domain and enter your custom URL -- including the subdomain -- in the text field.
Click the Test Domain link to test your new settings and, if Tumblr validates your new URL settings, click Save to finish the process.
Tips & Warnings
- If Tumblr is unable to successfully validate your new settings, its Test Domain tool identifies the errors. Fix all listed problems either by editing your Tumblr or your DNS records settings and select "Test Domain" again.
- It may take up to 72 hours after editing your domain name settings for DNS servers around the world to update their records. During that time, some visitors may be unable to visit your blog by typing its new URL address.
- Your registrar's DNS records editor may use terms other than "Host" or "Answers" when referring to the various values you can edit. Refer to your registrar's online documentation or contact its support team if you experience difficulties while creating a new DNS record.
- Selecting the wrong DNS record type or entering incorrect values can prevent visitors from being able to access your entire website. Contact your registrar before editing your domain name's DNS records if you are unsure how to create a valid CNAME DNS record.