IP leasing

The word came into networking with DHCP. Its standard of October 1993 called the period a device may use an address a "lease", citing a 1989 paper on file caching. It even let a client ask for "an infinite lease". That is the lease in "IPv4 lease time": a router lends a device an address, and the device renews it, by default when half the lease has passed. It is also how a home line's dynamic IP address works.

Leasing whole blocks between companies came later, with the address market. In 2011 a bankrupt network equipment maker, Nortel, sold 666,624 addresses to Microsoft for 7.5 million dollars, 11.25 dollars each, through ARIN's new transfer policy. Renting blocks grew out of that market, and APNIC's chief scientist now reviews sales and leases side by side each year.

The holder, or lessor, keeps the block registered in its own name. ARIN asks lessors to record the tenant in its whois as a reassignment, although the lease contract itself stays private. The holder also authorises the tenant's network to announce the block, often with a route origin authorisation (ROA) in the registry's RPKI system. The 2024 study counted 31,156 ROAs covering leased blocks.

The tenant, or lessee, then announces the block from its own network. Some bring it to a cloud provider instead. AWS, for example, asks for a ROA naming its own AS numbers and does not charge its hourly IPv4 fee on addresses customers bring. When the lease ends, in ARIN's words, "the lessor can demand that you return and stop using the addresses".

One broker publishes its sale prices, and APNIC's chief scientist tracks them every year. An address cost just under 10 dollars before 2016 and 45 to 60 dollars by the end of 2021. In the 40 days to 10 January 2026 the mean was 22 dollars, with a large block selling for 9 dollars an address. Lease prices are less visible, because leases are private contracts. The one broker that publishes them saw its average lease price fall 15 percent during 2025, while sale prices fell 50 percent.

Cloud providers pass the cost on. Since 1 February 2024 AWS has charged 0.005 dollars an hour for public IPv4 addresses, about 3.60 dollars a month each. It said the cost of acquiring one had risen more than 300 percent in five years.

The 2024 study found leased blocks about five times as likely as other blocks to be announced by a network on Spamhaus's ASN-DROP list. The shares were 1.1 percent of leased blocks against 0.2 percent of the rest. Spamhaus lists a network only after finding evidence that cybercrime groups or "bulletproof" hosts control it. It also notes that since IPv4 ran out, blocks are "typically" handed to customers by IPv4 brokers and move far more often than they used to.

A block keeps its history when it changes hands. The registries hold returned blocks back for months or years for exactly this reason, so that reputation services and routing records can see the old use end. When a leased block moves to a new tenant, the record of the last one comes with it.

Proxy sellers commonly describe ISP proxies as addresses leased from internet providers: blocks registered to a provider and announced from servers in a data centre. The 2024 study adds that commercial VPN providers "often lease different address spaces on a short-term basis".

Our free proxy list shows how common borrowed space is. On 19 September 2026 we matched 4,036 of its live proxies to their registry records. For 15.8 percent, the block was registered in one country and announced by a network registered in another. That is the pattern a lease leaves, though a multinational announcing a subsidiary's block looks the same. The largest groups were blocks registered in the United States and announced by networks in Indonesia, Colombia, Venezuela and Mexico. Another large group was blocks registered in Singapore and announced by networks in China.

For a proxy buyer the checks are the same as for any rented space: who holds the block, which network announces it, and which blocklists it is on. Leases end, so the same block can serve a new tenant next month.