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Acquiring IP Addresses

Make sure you have an authorized public IP address space assigned to your organization.

Do not make one up! Remember, every host on your network that runs TCP/IP must have at least one  IP address.

In assigning IP address space to end users, ENS takes guidance from assignment policies and procedures set forth in RFC 2050. These guidelines were developed to meet the needs of the larger Internet community in conserving scarce IPv4 address space and allowing continued use of existing Internet routing technologies.

ENS encourages the use of the following address conservation measures where appropriate:

  • VSLM (Variable Length Subnet Mask) RFC 2050
  • Private / Reserved Addresses RFC 1918
  • NAT (Network Address Translation) RFC 1631
  • DHCP (Dynamic Host Configuration Protocol) RFC 2131

RFCS can be looked up at this site

IP address spaces can be obtained by either of the following methods. Allow at least 3 weeks if making the request by postal mail.

  • ENS

If you require less than eight Class C networks to satisfy your request you may make your request to the ENS NOC. Note that all requests for IP Addresses will require written justification.

ENS IP Request Forms and Instructions:  

Adobe /sites/doa/pages/ots/otm/​lanet/IP_Address.pdf
Contact ENS NOC at (225) 219-4860 or for clarification if needed when making your request.

IP Addresses are only available to ENS subscribers. There are no fees charged for use of IP Addresses.

IP Addresses issued by ENS are the property of OTM. In the event of cancellation of ENS services, addresses must be returned (use discontinued) within 30 days of cancellation of ENS services.

  • American Registry for Internet Numbers (ARIN)

If you require eight or more Class C networks to satisfy your request you may make your request to the ARIN.

This is the organization charged with, among other things, assisting network administrators in registering IP network addresses. To obtain a network address space you will be required to complete a template, which can be obtained from the ARIN. The template includes instructions on how to complete and submit your request. ARIN can be contacted at:
Phone: 703-227-0660
Fax: 703-227-0676