He’s sitting on a stack of sweet, sweet IPv4 addresses … and needs some advice

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Credit: flickr/James Cridland

“ISP wants a /24 back, what’s it worth?” The question comes from a user of the Reddit section devoted to networking … and I’m afraid the answer eventually boils down to “it depends.”

First of all, a /24 refers to a block of 256 contiguous IPv4 addresses, which as everyone knows have become a scarce commodity. The Reddit user explains:

"I work for a school district that is also involved with community Internet service. Because of this, we have had 3 separate public /24 IPv4 address blocks since about 1995.

"Every time we contact our ISP for something, they ask for a /24 back. We could probably do this if we took some time to restructure everything and moved all our services to the other two /24s. I know we should be good "internet citizens" and just give the address space back … but if we give these addresses up our chances of ever getting another contiguous block on our budget is 0. They want the space back because the addresses are now valuable.

"So, if we do decide to gives the ISP one /24 block back, are they worth anything? Should we ask for something in return from our ISP?"

A spirited discussion ensues offering decidedly different points of view, ranging from contentions that such a request from an ISP is “super unprofessional” to actual dollar amounts -- $10 per address was the consensus -- and other forms of compensation that the fellow’s organization could reasonably expect in return for forking over one /24. Meanwhile, there were other voices expressing skepticism as to whether the addresses actually belong to the organization at all, at least in the legal sense that a web server or laptop would belong to it.

After reading the string this morning, and deciding that an official response might help clarify matters, I sent a few questions to a public relations representative for the American Registry for Internet Numbers (ARIN). A few hours later I received the following statement from John Curran, president and CEO of ARIN, who by then had also addressed similar remarks to the Redditor who started the discussion:

“The IPv4 addresses may have been assigned to you via your ISP, in which case your rights to them are rather limited. If this is the case, you should be prepared to eventually operate with fewer public IPv4 addresses, as your ISP can reclaim all or some of them and use elsewhere and you have no ability to prevent that. Note that changing ISPs is likely to have the same outcome, as your new ISP is likely to provide for your use a much smaller IPv4 assignment and note that it is specifically for the duration of your service contract.”

On the other hand …

“The IPv4 addresses may have been assigned to you by one of the registries in the Internet Number Registry System - this includes the IANA and the Regional Internet Registries - ARIN, RIPE NCC, APNIC, LACNIC, and AFRINIC at present, and their predecessors (such as the InterNIC, SRI-NIC, etc.) If this is the case, you have rights to the address block, and only your organization can update the entry in the Internet numbers registry system.

“If you are in doubt, you can reach out to the RIR which administers the IP address block entry, and ask about who it is assigned to and whether it’s under your control or the ISP's.”

While the latter seems more likely, it wasn’t clear from the discussion that anyone was sure.

In other words, it depends.

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