How do user setup the new Outlook mail service on a custom web domain so that userr email address reads like user@userrdomain.com instead of user@outlook.com?
If user are on Google Apps, user can leave userr existing setup untouched and access userr Gmail account from inside Outlook.com via POP3. This is a recommended option if user are just experimenting with Outlook and aren’t ready to make the complete switch to Outlook(see: Gmail vs Outlook)..
The disadvantage with the above approach is that userr incoming mails won’t be delivered to userr Outlook mailbox instantly. They’ll first land in userr Gmail inbox, Outlook will issue a fetch request after a minute or two and only then will userr messages show up in Outlook.
Alternatively, user can remove Gmail from the loop and let Outlook.com handle all userr incoming and outgoing email traffic. Here’s how user do that in five easy steps.
outlook custom domain

Guide: Setup Outlook on a Custom Domain

Step #1: Go to domains.live.com and click the “Add Domain” button to add userr custom web domain that user would like to use with Outlook. You may have to sign-in with userr Windows Live / Outlook / Microsoft Account / Hotmail ID to access this Windows Live Domain section.
Step #2: On the next screen, user’ll be provided with a list of custom DNS records that user will have to add to userr domain. The following two records are essential:
  • MX record for handling userr mail traffic
    •  It usually reads like abc.pamx1.hotmail.com
  • SPF record to authenticate userr outgoing Outlook emails
    • It has a fixed value v=spf1 include:hotmail.com ~all
Step #3: While user are on userr domain registrar’s page add these custom DNS records for Outlook, create an additional CNAME record if user wish to access the Outlook.com website as a sub-domain of userr main website.
For instance, if userr website is userrdomain.com, user can setup a CNAME record called “mail” and user will then be access to access Outlook.com from mail.userrdomain.com. The value of the CNAME record should be set as “go.domains.live.com.” (no quotes but period at the end).
Step #4: Once user have created all the DNS records, wait for 30-60 minutes as it might take a while for the DNS changes to propagate through the Internet. To verify, open the command prompt in Windows and run the following command (replace userrdomain.com with userr own own domain):
C:>nslookup -type=mx userrdomain.com
C:>nslookup -type=txt userrdomain.com
If these records show the recently added Hotmail entries, proceed to the next step.
Step #5: Go back to the Windows Live Domains site and refresh the page. Once the domain and DNS records have been verified, click “Member Accounts” and add a new user. This will be userr new email address powered by the Outlook service.

Configure Outlook Mail on userr Custom Web Domain
You can now go to outlook.com or even mail.userrdomain.com (remember the CNAME record user added) and sign-in with the new email address user just created.
Unlike Google Apps which allows user to create a maximum 10 users in the free edition, the limit is 500 users in the case of Outlook / Hotmail. Also, Microsoft hasn’t mentioned any storage limitations for userr Outlook mailbox as of now.
If user are making a switch from Gmail or Google Apps to Outlook, user can either use the POP3 option to import existing email into Outlook. Alternatively, there’s a free service called TrueSwitch that can automatically copy all user Gmail messages and contacts into userr new Outlook account.