Which SWIP Type Is Right For You?

Which SWIP Type Is Right For You?

What is SWIP and who can use it?

The Shared Whois Project, or SWIP, is used by Internet Service Providers (ISPs) and Local Internet Registries (LIRs) to submit reassignment information to ARIN. Current policy stipulates that each IPv4 assignment of a /29 or more and each IPv6 assignment that is /64 or more needs to be registered in the Whois directory via SWIP, or an ISP/LIR can host their own publicly accessible RWhois service. While this is a current policy requirement, it also ensures the quality and accuracy of data within ARIN’s Whois.

The Administrative (Admin) or Technical (Tech) Point of Contact (POC) for an organization that holds a Direct Allocation or Reallocation can submit SWIPs to ARIN and register reassignments or reallocations of IP addresses to their downstream customers.

It is important to note that IP addresses can only be reassigned or reallocated from a Direct Allocation or Reallocation. Reassignments and Reallocations cannot be made from Direct Assignments or Reassignments.

What are the different types of reassignments?

There are three different types of reassignments that can be used when reassigning IP addresses to your downstream customers. They are:

  • Reassign Simple

  • Reassign Detailed

  • Reallocate

Each of these can be accessed through your ARIN Online Account using the “Reassign Addresses” feature.  For more information, please see James Ricewick’s blog post “Let’s Talk About A Quick And Easy Way To SWIP”.

Reassign Simple

An ISP/LIR should use Reassign Simple to reassign IP addresses to downstream customers who will not be managing their own abuse complaints, do not need to maintain their own in-addr.arpa delegation, and do not have the need to further reassign/reallocate to their customers. Any modifications to the reassignment must be made by the upstream ISP/LIR that created the reassignment. There will be no Organization Identifier (Org ID) or POCs created when using this reassignment type.  POCs listed on this type of reassignment will be the POCs of the ISP/LIR that conducted the reassignment.

Reassign Detailed

An ISP/LIR should only use Reassign Detailed when the downstream customer will be managing their own abuse complaints, necessitating the need to have their own POC information on the reassignment, and wants the option to maintain their own in-addr.arpa delegation. However, using Reassign Detailed does not allow the reassignment to be further reassigned/reallocated to their customers.

During the generation of the reassignment, an Org ID and a POC can be created for the downstream customer.  Another option, and preferred by many downstream customers, is that the ISP/LIR insert the reassignment into an already established Org ID. This allows the downstream customer to easily manage their reassignments in an Org ID for which they are already authoritative.  This can also help ensure the proper POCs are being contacted for abuse complaints.


An ISP/LIR may Reallocate IP addresses to their downstream ISP/LIRs. Reallocate has all the same functions as the Reassign Detailed, with one major difference; Reallocate enables the downstream ISP/LIR to further reassign/reallocate to their downstream customers.

In short, you would use:

  • Reassign Simple if you are going to manage in-addr.arpa delegations and abuse complaints for your end customer

  • Reassign Detailed if your end customer will be managing in-addr.arpr delegations and abuse complaints

  • Reallocate if your downstream customer is an ISP/LIR who needs to further reassign/reallocate to their customers

How do you submit a SWIP?

As James outlined in his blog post, there are multiple methods an ISP/LIR can use to register their reassignments in ARIN’s Whois:

  • Email based templates

  • RESTful provisioning

  • ARIN Online

Please check out James’ blog for more information on using ARIN Online to submit your SWIPs.

If you would like to discuss which SWIP type is right for you, please contact a member of our Registration Services team at 703.227.0660 or submit an Ask ARIN ticket from within your ARIN Online account.

Post written by:

Doreen Marraffa
Resource Analyst

Doreen joined ARIN in April 2003 and currently reviews and evaluates ASN requests, change of authority requests and responds to both Ask ARIN and telephone requests. You’re likely to be able to meet Doreen at an ARIN Public Policy and Members Meeting. In addition to enjoying helping customers achieve their goals with ARIN and answering customer questions, Doreen is an avid tennis player and cookie baker.

Recent blogs categorized under: Tips

Sign up to receive the latest news about ARIN and the most pressing issues facing the Internet community.


IPv6 •  Public Policy •  Caribbean •  Updates •  Grant Program •  Customer Feedback •  ARIN Bits •  Fellowship Program •  Tips •  Internet Governance •  IPv4 •  Security •  Outreach •  Elections •  RPKI •  Training •  IRR •  Data Accuracy