1. Login to Blogger, go to Settings > Publishing > Blog Address. Click on Add a Custom Domain Name.
2. Add Custom Domain Name, add in your new domain name www.your-domain.com and click save.
3. You should now get an error message. This error shows you the details you need to properly set up your new domain so keep this page open for the next step. The first CNAME is the same for everyone. The second is a specific CNAME for your blog.
4. Login to your 1and1 control panel, scroll down until you see the heading “Domains” and click Domain Centre.
5. Click the checkbox beside your domain and select Domain Settings > Edit DNS Settings.
6. Under Basic DNS Settings choose 1&1 name servers, under Advanced DNS Settings choose Other IP address and in the space for IPv4 Address enter 220.127.116.11 and save.
7. Go back to Domain Overview Dashboard, click Add Domain > Create Subdomain. Enter the first Name/Host/Label field from Blogger, which is www
8. Click on the subdomain and click DNS Settings. Under Advanced DNS Settings choose CNAME and enter the first Destination/Target/Points To from Blogger, which is ghs.google.com
9. Go back to Domain Overview Dashboard, click Add Domain > Create Subdomain. Enter the second Name/Host/Label field from Blogger, which is unique to you and will look like 00AA0AAAAA
10. Click on the subdomain and click DNS Settings. Under Advanced DNS Settings choose CNAME and enter the second Destination/Target/Points To from Blogger, which is unique to you and will look like gv-a0aaaa0aaaaaa.dv.googlehosted.com
11. On your domain settings for your custom domain you should now see the URL you bought and two subdomains.
12. Go back onto Blogger > Settings > Publishing > Blog Address and enter your domain name and hit save. This time there shouldn’t be an error. Make sure to tick the option of redirecting from domain-name.com to www.your-domain.com.
After performing the above steps you should have successfully parked your 1and1 domain to your blog.