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DNS Registrations for Your Subnet

This article applies to: DNS

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If you're responsible for network connections in your department or building, you need to register all the network devices in DNS as per University Policy 5.7, Network Registry. For more information, see How to Comply with Network Registration Policy.

Your first step should be to register as a network administrator (net admin).

Register as a Net Admin with the Cornell Hostmaster

Email with:

  • IP address range(s) of your subnet(s), for example
  • Name(s) of your domain(s), for example
  • Name, NetID, and email address of each person who has responsibility for these networks, including yourself.

After registering as a net admin, you will be able to:

  • Update info about your subnets, domains, and hosts in Cornell's DNS database.
  • Receive announcements of changes that affect your subnet(s), and announcements of new services such as the DNS database and DHCP support.
  • Create an escalation path for CIT to use if a serious problem needs to be reported at night or on a weekend.

Choosing Between DHCP and Manually Configuring DNS


DHCP (Dynamic Host Configuration Protocol) is designed to allow you to administer a large IP network more efficiently. A central network server distributes configuration information such as DNS servers, subnet mask, gateways and most importantly, IP address, to individual machines.

CIT offers a campus-wide DHCP service.

DHCP reduces paperwork while increasing your control over your subnet. DHCP can:

  • Automate some subnet record-keeping, such as tracking which IP numbers are in use, and who is using them.
  • Document visitors on the LAN.
  • Centralize network configuration.
  • Facilitate major changes in the IP protocol configuration. This means changes such as campus DNS or the local subnet's gateway can be made without an administrator visiting each machine.
  • Enforce IP address distribution restrictions for your subnet.
  • Make it easier for users to move between home and office.

For more information, see Plan and Implement DHCP on Your Subnet.

Manually Enter DNS Registration

Use one of these methods:

  • Update one machine at a time via the host list web page (requires Cornell login and access via campus network or CU VPN).
  • Update multiple machines at once via the batch load interface (requires Cornell login and access via campus network or CU VPN).
  • Tips:
    • Create a record: addhost hostname ipaddr
    • Record the MAC address: addmac ipaddr macaddr
    • Record the NetID: chgowner hostname netid
    • More commands: Batch language help
Recording the MAC address and NetID are required to comply with university policy (for details, see How to Comply with Network Registry Policy).


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