By default all domains are configured to use our name servers. You may, if you wish, opt to use third pary nameservers. To configure nameservers for you domain, go to My Account > Domains > your.domain.name > Nameservers
Caution
If you change your nameservers away from ourselves, you will have to manage all DNS records through your third party provider. The Manage DNS Zone functionality will no longer work as we will no longer control your DNS records.