Autonomous System Originations (Origin AS)

The Origin Autonomous System (AS) field is an optional field collected by ARIN during all IPv4 and IPv6 block transactions (allocation requests, reallocation and reassignment actions, transfer and experimental requests). This additional field is used by IP address block holders (including legacy address holders) to record a list of the Autonomous System Numbers (ASNs), separated by commas or whitespace, from which the addresses in the address block(s) may originate.

Collecting and making Origin AS information available to the community is part of the implementation of Policy ARIN-2006-3: Capturing Originations in Templates, included in the ARIN Number Resource Policy Manual (NRPM) Section 3.5, Autonomous System Originations. This information is available using our Bulk Whois service.

Using the Origin AS Field to Validate LOAs

Origin AS information can assist Internet Service Providers (ISPs) in determining the validity of a Letter of Authority (LOA) provided by a customer when requesting to manage an IP address block. In cases where tools like Whois or an examination of registry information does not provide a clear case for a customer’s holdership, the ISP can request that the customer configure the Origin AS field to match the ISP’s AS. If a customer is an IP address block holder (including legacy address holders), they can easily set the Origin AS attribute using an ARIN Online account. Organizations that don’t have current contact information associated with their address block will need to be validated initially by ARIN before updating their network record. Requiring an Origin AS update confirms to the ISP that the IP address block owner is verified and correct.

Configuring an Origin AS

The Origin AS can be set by the appropriate Point of Contact (POC) (Admin, Tech, or Resource) in one of two ways:

• Within ARIN Online: ARIN Online allows authenticated users to manage their network registration records.
• Using the Registration RESTful Web Service (Reg-RWS): This API allows for automated and authorized updates for an IP address block by the authorized contact to occur via ARIN’s provisioning system.

Managing Network Resources

To manage network resources within ARIN Online, you need an ARIN Online account.

Once you have your ARIN Online account, link your ARIN Online account to an Admin or Tech Point of Contact (POC). This POC must be associated with the Org ID that manages the resources you need to access.

If your account does not have access to the resources, you can view information on transferring resources before you request that they be transferred to you.

Using ARIN Online to Configure an Origin AS

To configure an Origin AS for an IP address block as an associated Admin, Tech, or Resource POC:

1. Log in to ARIN Online, select Networks (NETs) on the dashboard, and choose the Net Handle that contains the IP address block for which you want to configure the Origin AS.
2. Select Modify from the Actions menu.

In the View & Manage Network page, in Modify Network Record:

1. In the Origin AS field, enter an ASN.
2. Choose Submit.

A notification is displayed if the information was successfully saved, and the Origin AS appears in the Network Information section:

You can also configure Origin AS information in ARIN Online when reassigning or reallocating IP addresses.

Using Reg-RWS to Configure an Origin AS

The Origin AS field can be configured if you are using Reg-RWS to submit registration data to ARIN. Reg-RWS allows you to configure applications or scripts that use the Reg-RWS API to connect to the ARIN database. The application can access a URL to get information about records, create new records, modify existing records, or delete records in the database. Additional information about the record (for example, organization data) is contained in an XML payload that is sent or received. The Origin AS field is located in the NET payload, which contains information about the IPv4 or IPv6 network.

For more information on Reg-RWS, visit:

• Automating Record Management with Reg-RWS
• RESTful Payloads

Querying the Origin AS Field Using Registration Data Access Protocol (RDAP)

ARIN’s RDAP implementation supports searching for networks that have a specific AS Number in the Origin AS field.

• To perform this query from Whois/RDAP (the RDAP web interface), refer to Searching for an Origin AS.
• To perform this query from the command-line interface, refer to instructions for querying the Origin AS on the RDAP page.