During registration you have the option of setting your domain name servers, or DNS.
You have two options, but you can only choose one:
Park Domain Name And Utilise Free Services
If you wish to use the free and paid services 1st Domains offers, then you should choose to 'Park' your domain name. This will allow us to control the servers for your domain name and offer you free services such as email forwarding, and URL redirection. If you choose to use our paid services, this will require our Name Servers.
Delegate Domain Name(s)
If you operate your own DNS servers, or you have been given the DNS servers by your ISP or web hosting company, specify them here. If you choose to delegate your domain names to a DNS host we cannot offer you our free or paid services such as email or web hosting, but you can switch back to us at a later stage should you wish.