The internet ran out of fresh IPv4 addresses years ago, yet most networks still depend on them every single day. 

That gap between supply and demand is exactly why a busy secondary market now exists for companies that need more space.

Buying on that market is not as simple as adding items to a cart and checking out. The process involves registry rules, transferring paperwork, and real risk if the addresses you receive turn out to be dirty.

This guide walks through why the shortage happened, what to check before you buy, and how a transfer actually works. The goal is to make a confusing purchase feel routine.

Why IPv4 ran out in the first place

Back in early 2011, the Internet Assigned Numbers Authority announced that the central pool of IPv4 space had been exhausted. 

In the years after, the regional registries handed out the last of their blocks, which pushed everyone toward buying and selling among themselves.

IPv6 was meant to solve this problem, but adoption has stayed slow and uneven across the industry. Plenty of hardware, software, and service providers still lean on IPv4, so demand has never really cooled off.

The buyers are not a niche group either, ranging from ISPs and telcos to hosting providers and large enterprises. 

Each of them needs routable addresses to run services, and many are scaling faster than their original allocations were ever designed to allow.

Why does the market feel so confusing

There are only a handful of legitimate places to buy IPv4 blocks, and clear information about the actual transfer steps is hard to find. 

That lack of transparency is what makes the whole thing feel risky for a first-time buyer.

On top of that, there are no published rules that guarantee the addresses you buy are clean and legitimately owned. A buyer can easily end up with space that is blacklisted or tangled in an ownership dispute.

What to check before you buy

The single most important question is whether the seller actually owns the block free and clear. A serious broker qualifies every seller first, confirming clean ownership before that block is ever offered to you.

The second question is reputation, since an address that was once used for spam or abuse may sit on industry blacklists. 

1. Inheriting blacklisted space can quietly break your email delivery and damage your network standing from day one.
2. This is where blacklist screening earns its keep, because checking each address by hand against a few popular lists is slow and incomplete. 
3. Brander Group runs every address against more than 100 global blacklists in under a day and hands you a detailed report.

That report shows which addresses are listed, where they appear, and how to get them removed. 

Seeing this before any money changes hands lets you negotiate or walk away instead of cleaning up a mess later.

It is just as important to confirm the block is fully routable and accepted by the major networks. Space that looks clean on paper is of little use if upstream providers will not route it for you.

How the transfer actually works

Once you decide to buy IP addresses, the registry transfer is the part that tends to catch people off guard. A fully managed broker handles the heavy lifting, so your job is mostly to sign, pay, and submit a ticket.

It usually starts with pre-approval and verification, followed by signed purchase agreements between both parties. 

Payment then moves through a wire transfer or an escrow service, which protects the buyer and the seller until the deal is complete.

From there, the buyer and seller each submit a transfer ticket, and the regional registry reviews the request. 

Any registry fees are paid, the Whois records are updated to the buyer’s details, and the funds are finally released to the seller.

Across ARIN, RIPE, and APNIC, a typical transfer runs about two to three weeks. Each stage takes a few days, so clean paperwork matters far more than trying to rush the timeline.

Most reputable brokers publish region-specific transfer guides for each of these registries. Reading the one that applies to your situation ahead of time strips away a lot of the uncertainty about what the registry will ask you to provide.

Choosing the right partner

Because so much can go sideways, the broker you pick shapes the entire experience. Look for one that works with both buyers and sellers, since that dual role gives them tighter quality control from start to finish.

Fixed and competitive pricing is another good sign, as it spares you the guesswork and pressure of an open auction. 

Responsive support that answers by phone and email also helps a great deal when a registry question comes up in the middle of a transfer.

It is also worth asking how a broker sources its inventory. Some uncover legacy blocks that have sat unused for years, clean them up, and bring genuinely fresh supply to the market rather than reselling the same tired space.

Matching block size to real need

Block sizes range widely, from a small /24 right up to a large /12, so your provider should match the supply to what you actually need. 

Buying more than you can justify ties up budget, while buying too little sends you back to the market sooner than you would like.

A good partner will ask about your growth plans before quoting anything. That conversation helps you avoid both overspending today and a second scramble for space next year.

A few final pointers

Treat an IPv4 purchase like any other piece of infrastructure spending rather than a quick transaction. 

• That means doing real due diligence on ownership, reputation, and the support you will get if something goes wrong.
• Keep records of every agreement and ticket, since registries can ask questions long after a transfer closes. A tidy paper trail protects you if ownership is ever queried down the line.
• It also pays to confirm the region you are buying in before you commit. An address block that suits an ARIN buyer may carry different transfer conditions in RIPE or APNIC, and a knowledgeable broker will flag that early.
• If you are new to all of this, a free consultation is a sensible first step before you commit to anything. 

A good broker will scope out the block size, region, and budget that fit your situation and walk you through the timeline honestly.

The bottom line

The IPv4 shortage is not going away any time soon, and the secondary market remains the practical way to grow your address space. 

With the right broker, verified and clean blocks, and a clear transfer plan, the process is far less daunting than it first looks.

Get the fundamentals right and your new addresses will start working for you almost immediately. 

Cut corners on ownership checks or blacklist screening, and a cheap block can cost you far more than you saved.