ACSP Suggestion 2009.16: Accepting Previously Used Address Space


Author: Michiel Klaver   
Submitted On: 15 September 2009


When requesting address space, one should be able to indicate whether receiving previous used address space would be unwanted or not.

When assigning address space, ARIN should also notify receivers if it’s re-used or virgin address space.

When address space got returned to ARIN and there is evidence of abuse, they have to mark that address space as ‘contaminated’ and only re-assign that space to new end-users who have indicated to have no problem with that.

Timeframe: Immediate

Status: Closed   Updated: 29 September 2009

Tracking Information

ARIN Comment

29 September 2009

Since this suggestion has three main components, we will answer each of them separately.

You suggest that all requestors be allowed to choose whether or not to accept previously used IP address space from ARIN.

While this may be desirable to many in the community, there are a multitude of reasons why ARIN should not do this. As stewards of the Internet number resources, and in adherence to the conservation principles outlined in RFC 2050, ARIN makes every attempt to efficiently allocate its available pool of IP number resources. Today, many of the allocations and assignments ARIN issues daily are from “recycled” space, given out for a second or even third time due to returns from former registrants or account revocations. Allowing resource recipients the choice of whether to accept recycled space would delay the issuance of address space, and force staff to have “fresh” back-up space always available, a task that will become increasingly difficult as the global pool of IPv4 addresses is depleted.

You suggest that ARIN notify requestors when they are being issued recycled IP address space, which is something that ARIN can and will do.

Finally, you suggest that IP address space returned to or reclaimed by ARIN that shows evidence of abuse, be marked as contaminated and re-issued only when a requestor chooses to accept that space.

There are a number of issues surrounding this part of the suggestion. The terminology “evidence of abuse” is subjective and difficult to determine without additional criteria. There are numerous RBL operators utilizing different policies, practices, definitions, etc., thus no single definition likely exists for the term “contaminated space”. It would be very difficult for ARIN to determine whether an address block was truly contaminated or truly clean with any degree of certainty. Because of the issues cited, and other potential issues, ARIN will not be able to implement any aspect of this part of your suggestion.

In closing, we’d like to offer some additional information on the procedures that ARIN follows when re-issuing previously used or “recycled” IPv4 address space that the community may not be aware of, and which may help to allay some concerns.

  1. ARIN holds all returned and revoked address space for at least 1 year (longer if it is still on blacklists) to clear filters prior to re-issuing.
  2. ARIN checks routing tables to ensure that the space isn’t being routed prior to re-issuing (if it is being routed, we contact the organization that is routing the block and ask them to stop).
  3. Per ACSP 2008.2, ARIN checks some of the well-known RBL operators to see if the block being re-issued is listed.
  4. If the block is being listed, ARIN attempts to contact the RBL operator to notify them that the block is being reissued to a new organization. If multiple RBL operators list the block, and we are unable to contact them, ARIN will pull the block and add it back to the hold list for future reference.