Alain Durand’s IPv4 reserve for IPv6 deployment

Alain Durand Put IPv4 Aside for IPv6’s Awkward Teenage Years

Why it matters

In 2008, Durand proposed an odd-looking ration: save a piece of the scarce old Internet for builders of the new one. The rule still has a job, even though its individual grants no longer look like those in his first draft.

Sofia Ren25 October 2026Reading Time 2 minLast update: 25 October 2026

Alain Durand; likeness based on his named RIPE NCC SEE 12 photo. The network background is imagined.

Summary

Alain Durand authored ARIN Policy 2008-5, proposing a contiguous IPv4 /10 reserved for needs tied to immediate IPv6 deployment. ARIN lists Board action on 5 January 2009 and implementation on 1 April 2009.
The original text allowed individual grants between /28 and /24. ARIN’s current request guide says a qualifying applicant receives a /24, with six months between grants under the policy.

IPv6 was supposed to make address scarcity yesterday’s headache. Alain Durand noticed that yesterday still answered the phone. A new IPv6 network might need IPv4 reachability for a key dual-stack DNS server or a translator while other parts of the Internet remained on the older protocol. In his 2008 ARIN proposal, he asked that a contiguous /10 be protected for precisely those immediate deployment needs. That is 4,194,304 IPv4 addresses in a reserve, not a gift of four million addresses to each applicant.

The rationing was deliberate. The proposal described /28 as the smallest individual grant and /24 as the largest, made repeat applicants wait six months, and required them to show that other allocations could not meet the need. Durand argued that the store had to last long enough for later IPv6 entrants. ARIN’s archive dates the Board action to 5 January 2009 and implementation to 1 April. Its wording linked the reserve to the final IANA /8 while leaving the exact choice of source block to ARIN staff.

At ARIN 35 in 2015, Durand returned to the arithmetic. A proposal to issue only /24s would make small prefixes easier to reach through common route filters, but it would reduce the number of possible grants from a fixed /10. The meeting transcript records his concern for future entrants and his reference to DNS continuity. He was arguing over the size of the spoon, not asking to empty the jar.

Today ARIN’s 4.10 guidance still describes a contiguous /10 for immediate IPv6 deployment, with a /24 per approved request. The six-month interval remains. Durand’s initial grant range and the present rule are different snapshots of the same practical bargain: scarce IPv4 goes to a demonstrated bridge into IPv6, while the reserve must serve people who have not arrived yet.