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IP Address Public Policy

IP addresses are loaned to NTT from the Regional Internet Registries (RIRs) such as ARIN and RIPE. In turn, NTT lends those IP addresses to our customers for use while connected to the NTT network. The size of the IP address loan varies and is solely based on the continually demonstrated and documented need of the customer.

Table of Contents

  1. Introduction
  2. Guidelines for Customers
  3. Documentation Required
  4. IP Address Justification (IPJ) Forms
  5. References

I. Introduction

The NTT IP Address Policy has been created with guidance from various Request For Comments documents (RFCs) and the existing policies of the RIRs from which NTT obtains IP addresses. See

Due to the dynamic nature of the internet, NTT reserves the right to change this document at any time without prior notice. Please check the NTT website for the latest version of this policy, as the latest version of the policy will supersede all others.

NTT distributes IP addresses with three goals in mind:

  1. Conservation: The objective distribution of globally unique IP address space according to the operational needs of customers. NTT tries to prevent stockpiling in order to maximize the utilization of IP address space.
  2. Routability: The distribution of globally unique IP address space in a hierarchical manner, which permits scalability in the internet routing table. The loan of IP address space by NTT does not guarantee routability, due to other ISPs routing policies.
  3. Registration: NTT is required by ARIN (American Registry for Internet Numbers) to provide information on which entity is using the IP space. This information can be provided to ARIN either via SWIP or an RWhois server. NTT documents the loan of IP addresses to a customer via a publicly available Referral WHOIS (rwhois) server. If a customer is assigned static IP addresses, the customer information will be added to our RWhois server. This information includes: customer’s name, company name if a business, postal address, e-mail address, IP address, and telephone number.

NTT realizes that conservation and routability can be conflicting goals. NTT will review individual cases when there are conflicts to try to work out an appropriate compromise.

II. Guidelines for Customers

NTT has developed the following guidelines that will be applied to customer requests for IP address space:

  1. IP addresses are loaned in blocks that conform to Classless Inter-Domain Routing (CIDR) boundaries. Customers should use classless technologies and routing protocols that support variable-length subnet mask (VLSM).
  2. IP addresses are loaned for the duration of the customer’s connection to the NTT network and must be routed on the NTT network. In the event that the customer disconnects from the NTT network or stops routing the addresses on the NTT network, a 30 day grace period will be given for the customer to renumber out of their loaned IP address space.
  3. At no time shall a current NTT customer use and/or announce NTT IP addresses that have not been specifically assigned to them. Former NTT customers and non-customers may not use and/or announce any NTT IP addresses except in cases where a formal agreement has been reached (e.g. BGP multihoming). Unauthorized use and/or announcement of NTT IP addresses will result in the immediate reclamation of the unauthorized IP addresses and may jeopardize current and future IP address loans from NTT.
  4. In the event that an NTT customer (Customer A) acquires/merges/takes over another NTT customer (Customer B), the resulting customer of record will be required to renumber “Customer B” into IP address space assigned to “Customer A”. Should the resulting customer require additional space to accommodate this renumbering, they will need to complete an IP Address Justification (IPJ) form (documenting their address space utilization) for review and approval by NTT.
  5. At any time, NTT may require a customer to justify its IP address loan. If the customer is unable to do so, its ability to obtain future loans may be jeopardized and its existing loan may be revoked.
  6. IP addresses are loaned to customers using a “slow-start” process. New customers will receive a minimal loan based on their immediate requirement. Thereafter, the size of loaned IP address blocks may be increased based on the speed that the customer utilizes all previously loaned IP address blocks.
  7. RIRs may set a maximum size of the IP address loan that NTT is allowed to make. If a customer requests a loan size that is above the RIR size limit, the RIR reserves the right to review and approve the loan. The RIR may have different guidelines than NTT does for reviewing and approving the loan and the customer would be required to adhere to the RIR’s guidelines in this instance.
  8. Due to the limited availability of IP (v4) address space, the practice of assigning a unique IP address per dialup user is discouraged.
  9. The Internet community filters IPV6 announcements based on the IPV6 allocations from ARIN. The allocations (and filtering) are necessary in order to minimize routing table expansion. Any customer requiring BGP multi-homing, now or in the future, should apply for Provider Independent (PI) IPv6 space directly from ARIN. ARIN can also allocate /48 critical infrastructure space if justified (eg. root domain operators). Customers with multiple connections to the NTT network may announce longer prefixes along with their ARIN allocation to effectively manage their inbound traffic, but the longer prefixes will not be propagated beyond the AS2914 backbone.More information regarding ARIN’s IPv6 assignment and allocation policies can be found here:
  10. When a customer requests an IP address space loan from NTT that will be used for IP-based web hosting, the customer will need to provide technical justification as to why they are providing IP-based web hosting instead of name-based web hosting. NTT is required to provide this information to the RIRs.

III. Documentation Required

Before NTT makes an IP address loan to a customer, the following documentation must be submitted by the customer. NTT will not begin the IP address loan process until all of the required documentation has been submitted. A link to the NTT IP Address Justification form is included in section IV.

  1. Documentation of existing IP address space usage. This shows how any space the customer has is currently being used, along with projections for the next 3 and 6 months.
  2. Documentation showing how the requested IP space will be used. This shows how the customer plans to use the space immediately, along with projections for the next 3 and 6 months.
  3. A network topology map for all requests of 128 IP addresses (/25) or larger.
  4. A description of the network routing plans, along with any protocols used and the protocol limitations.
  5. For customers requesting space for web hosting, a list of IP addresses currently being used for web hosting, and a list of domains being hosted. If IP-based hosting is being done, a list of technical reasons why named-based hosting cannot be done must be included.

This information will be used by NTT ONLY to justify the loan of IP addresses to a customer. The information may also be given to the RIRs if they request it as part of reviewing their loans to NTT.

NTT reserves the right to amend this policy at any time.

IV. IP Address Justification (IPJ) Forms

IP Address Justification (IPJ) Form, Microsoft Word version

IP Address Justification (IPJ) Form, plain text version

V. NTT Announcement of Customer-Owned IP Addresses

Customer may request NTT to originate route announcements of IP address space assigned to them by a Regional Internet Registry (RIR) from NTT’s Autonomous System Number (ASN). In such cases, NTT requires that the customer registers and maintains a Resource Public Key Infrastructure Route Origin Authorization (RPKI ROA) with AS2914 or another ASN communicated by NTT as the Origin AS. This is in order to show that NTT is authorized to announce the IP address space by the assignee. Requests to announce customer-owned IP addresses are reviewed on a case-by-case basis and it is at NTT’s sole discretion to originate or withdraw the route announcement, regardless of if a ROA exists

VI. References

[RFC 2050] Hubbard, K., Kosters, M., Conrad, D., Karrenberg, D., and Postel, J.,

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