Your IP address could not be determined at this time.

Reporting Reassignment To ARIN

As outlined in the ARIN Number Resource Policy Manual (NRPM), organizations that receive IPv4 or IPv6 address space allocations from ARIN directly or as a downstream customer of another organization must provide reassignment information.

ARIN makes allocations based on an organization's utilization history, projected requirements, and other information ARIN deems necessary. Therefore, initial allocations may be relatively small. Likewise, justification for subsequent address blocks is based on the verification of utilization supplied to ARIN in the form of reassignment information.

Information is to be provided to ARIN within seven days of the reassignment so that the public Whois service may be maintained efficiently. In addition, ARIN may request this information at any time. If the organization does not supply the information, ARIN may withhold future allocations, and in extreme cases, existing allocations may be affected.

ARIN requires organizations to submit information for all IPv4 reassignments of /29 and larger and IPv6 reassignments of /64 or shorter prefix within seven days of the subdelegation. For IPv4 blocks of /30 or longer prefix, ISPs may choose to provide utilization data via the Shared Whois Project (SWIP) or manually upon request. There are special reporting requirements for residential cable ISPs and residential customers.  Organizations may only submit reassignment data for records within their allocated blocks.

For more information regarding ARIN's database and registration records, click here.

Reporting Options

There are two methods for reporting reassignments:


Information about this method is available on the Referral Whois (RWhois) page.


There are three ways to report reassignment information via Shared Whois Project (SWIP): within ARIN Online, via the RESTful Web Service, and via email request forms. The RESTful Web Service and email request forms involve the use of an API key to authorize processing. To create an API key, log in to your ARIN Online account and select Your Account > Settings in the navigation menu. In the API Key Management section, choose Create API Key. The API key will be issued automatically.

Within ARIN Online

Creating Reassignments

To reassign network address space, you have the following options:

Option 1: View free blocks and reassign:

  1. Choose IP Addresses > Reassign Addresses from the navigation menu. A list of unassigned address space is displayed. (Note that users with over 10,000 NETS will not see this list. See the note at the end of the Creating Reassignments section.)
  2. In the list of networks, choose the network space that you want to reassign.
  3. Choose the size of the CIDR block to reassign, then choose Reassign.

Option 2: View networks and enter a range to reassign:

  1. From the Dashboard, under Account Snapshot, choose Networks to access the View and Manage Your Networks page. A list of NETS associated with you is displayed. (Note that users with over 10,000 NETS will not see a list of associated NETS. See the note at the end of the Creating Reassignments section.)
  2. In the list of networks, expand the informational panel for the network portion that you want to reassign. The actions available to you (depending on permissions and resources) appear under Net Actions.
  3. Tip: Copy the Network Address so that you can easily enter it later in the Reassignment Details screen.

  4. Choose Reassign. After choosing Reassign, follow the steps in the subsequent screens to complete the reassignment.
Note for Users With 10,000 or More Associated NETS
  • Choosing IP Addresses > Reassign Addresses will not provide the list of free blocks. You'll need to enter the IP address in the IP Address Range field in the Reassignment Details page and follow the instructions in the subsequent screens.
  • Choosing IP Addresses > Search will not display a list of NETS associated with you. You'll need to enter an IP address in its entirety and choose Search to display it.
Deleting Reassignments

First, find the network that was reassigned by selecting IP Addresses > Search from the navigation menu. Be sure that you’ve selected the option to include the networks that you’ve reassigned.

To delete a directly reassigned NET:

  1. In the list of search results, expand the informational panel for the NET.
  2. Under Net Actions, choose Delete to open the Delete Network page. The page provides information about the reassigned space and any contained reassignments of this space that were made.
  3. Choose Delete to remove the NET. Any additional reassignments that were made after the initial reassignment are also removed.

Caution: You can’t undo this deletion.

To remove individual reassignments from a list of reassignments of a space:

  1. In the list of search results, click the Network Name (for example, NET-DEV-001) to open the View and Manage Networks page for that NET.
  2. Choose Delete Reassignments. A list of the reassignments is displayed.
  3. Choose an individual network by clicking on the Network Name.
  4. In the View and Manage Network page, choose Delete.

Caution: You can’t undo this deletion.

Via the RESTful Web Service

ARIN has a RESTful web service that you can use to report reassignments.  This provisioning system allows for more secure interactions with ARIN's database and provides even stronger authentication on automated submissions.  More information is provided in the API documentation for ARIN’s RESTful web service.

Via Email Request Forms

The process for using email requests is detailed below. You must include the API key in the request form or send it from the email address associated with the API key to authorize processing.

Note: IPv6 simple reassigns cannot be performed using email request forms.

Which request form do I use when utilizing REST to create reassignments?

Since ARIN distinguishes reallocations from reassignments, it is important that you submit subdelegation information using the correct request form. If you submit reassignment information using the IPv4 Reallocate, IPv6 Reallocate, IPv4 Reassign-Detailed, or IPv6 Reassign request forms, the downstream organization must have a unique alphanumeric identifier (an Org ID). An Org ID can be created using the Reallocate or Reassign-Detailed request forms or using the organization request form.

There are multiple IPv4 and IPv6 request forms used to report reassignment information. Read the following descriptions to determine which you should use.

Used to remove subdelegations originally created using the reassign-detailed or reallocate request forms or to return a block of directly registered IP addresses.

To remove subdelegations, the request must be submitted with an API key associated with an ARIN Online user account linked to the upstream organization's Admin or Tech POC or the upstream's Tech POC for the resource.  These are also used to modify a network that is not a simple reassign.

Used to subdelegate IP addresses to a downstream organization that will further subdelegate the IP addresses to their own customers. These requests must be submitted by an ARIN Online user account linked to the parent organization's Admin or Tech POC, or the Tech POC for the resource.

Used to subdelegate IP addresses to a downstream organization that does not need to further subdelegate the IP addresses, but does need to maintain its own reverse name servers and/or display separate point of contact (POC) information.  It is submitted by an ARIN Online user account linked to the parent organization's Admin or Tech POC, or the Tech POC for the resource.

Used to subdelegate IP addresses to a customer that does not need to:

  • subdelegate the addresses to their own customers
  • maintain their own delegation
  • display their own point of contact (POC) information.

It can also be used to change the customer name and address information (but not the range) on an existing simple reassignment and to remove simple reassignments. It is submitted by an ARIN Online user account linked to the parent organization's Admin or Tech POC, or the Tech POC for the resource.

NOTE: IPv6 simple reassigns are only available in the RESTful web service.

POCs are not associated with simple reassignments. The customer receiving the reassignment will have the assigning upstream’s POCs and name servers.

Special Reporting Requirements

Residential Access ISPs

For organizations that have residential subscribers and assign address space to their access infrastructure to which their customers connect rather than to individual subscribers, IPv4 assignment information regarding each market area holding an address block should be submitted to ARIN using one of the methods listed above, with the network name used to identify each market area. Residential access ISPs must show that they have reassigned at least 80% of their current IPv4 address space, with a 50 to 80% utilization rate, in order to request additional addresses.

Each IPv4 assignment to a specific end-user (if holding /29 and larger blocks) requires the submission of a SWIP request form or use of an RWhois server. Requesters will also be asked to provide detailed plans for use of the newly requested space.

Residential Customer Privacy

NRPM allows organizations to privatize reassignment information for downstream end-user customers that are individuals, not organizations, and receive service at a place of residence for personal use only. ARIN recommends using version 5 templates to privatize residential customer information.  Version 5 templates allow the ISP to submit customer name and street address information for all customers, with a private flag available to designate which records are residential customers that should be private.  Records designated as private will have the customer name and street address removed when displayed in Whois. ISPs must still provide the customer's actual city, state, postal code, and country code.

ISPs using this policy must have accurate upstream Abuse and Technical POCs visible on the Whois record for the IP address block from which the addresses are being subdelegated.

Search Related Content


full site search

Examples: Resource Request Documentation Examples: Resource Request Documentation

Registration Services Help Desk

Interacting With ARIN

Monday through Friday
7:00 AM to 7:00 PM ET
Phone: +1.703.227.0660
Fax: +1.703.997.8844
Tips for Calling the Help Desk