To setup your own personal name server under the 1&1 registrar's online interface, please follow these steps:

1. Log into your Account (http://admin.1and1.com).
2. In the Domain Overview section of admin.1and1.com click on the new tab in the upper left section of the domain overview menu then click on Create Subdomain.
3. In the created Create Subdomain section select the domain you want to use as a nameserver on the right then fill in the left field with the prefix (example = ns1).
4. After this is created, locate the new subdomain (example = ns1.example.com) in the menu and click the check box to the left, then from the top menu click on the DNS section and click on Edit DNS Setting.
5. In the DNS Setting page that loads, make sure the Domain Data is set to DNS the Basic DNS Settings :: Name Server section set to “1&1 nameserver” (Note: This is because they are your registrar and they need to send the referral for the personal name server to the root level name servers).
6. Then in the Advanced DNS Settings section of that page under “IP Address (A record)*” change it to “Other IP Address” and put in the IP of the server that will host your DNS.
   
   Optional Repeat the above steps for any other name servers you want to make (example = ns2.example.com).
   
   
7. Once the first changes have taken place, and the status in the 5th column ('status') of the domain overview windows shows Ready you can set the domain to use itself as a nameserver. Trying to set it prior to the ns1 and ns2 subdomain changing over will give you an error that it can't make the change because of the domains status.

Now that you have created the nameserver entries, you need to tell the domain which you set your nameserver up on to use itself as a nameserver. In our example go to example.com in the Domain Overview section, click the check box to the left of it then click on the Edit DNS Settings of the DNS drop down menu. Under the Advanced DNS Settings section of the DNS Settings page that loads change the primary and secondary nameservers to the nameserver(s) you created (ns1.example.com and ns2.example.com).