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This Time, There Really Are NO IPv4 Internet Addresses Left

Thursday, Oct 17th, 2019 (4:06 pm) - Score 39,421

The RIPE Network Coordination Centre (RIPE NCC), which manages regional distribution of internet addresses for the UK, Europe, Middle East and parts of Central Asia, has confirmed that their final reserve pool of Internet Protocol v4 (IPv4) addresses will completely run out in November 2019.

Strictly speaking the Regional Internet Registry (RIR) started running out of address space in 2012 and began rationing the little they had left. Fast forward a few years and at the start of October 2019 it was confirmed that they only had 1 million IPv4 addresses left in their available pool (out of 4 billion addresses total), “which we expect to run out in November 2019“; these are currently being distributed via smaller prefixes (/23s and or /24s)


At present the Internet Protocol v4 standard, which is part of a seamless technology that helps to connect your computer/devices with the online world (like an ID number for your connection), is still important for a lot of internet-capable hardware and software. Thankfully many ISPs, devices and services have now introduced “newer” IPv6 addresses, although some still have a lot of work to do (e.g. TalkTalk).

Example IPv4 IP Address:
Example IPv6 IP Address: 0:0:0:0:0:ffff:7b55:435a

Admittedly providers will be using both IPv6 and IPv4’s side-by-side for many years to come because if they were to go completely IPv6 today then a lot of sites, services and devices would run into connectivity problems; many still cannot understand the longer v6 standard (home to about 340 trillion trillion trillion addresses).

Indeed when RIPE NCC surveyed 4,161 network operators and other stakeholders earlier this year, a third ranked IPv4 run-out as among the top-three challenges facing their organisation (54% also said they will need more IPv4 addresses within the next 2-3 years.. oh dear).

A Spokesperson for RIPE NCC told ISPreview.co.uk:

“On October 2, we announced that we had one million IPv4 addresses left in our available pool, which we expect to run out in November 2019. Any IPv4 addresses we recover after this point will be allocated to new entrants via a waiting list. This will probably be a few hundred thousand addresses – not much compared to the many millions that networks in our region need.

It’s important to note that we have been in a state of IPv4 exhaustion since 2012, when we reached our final allocation from IANA. IPv4 ‘run-out’ has long been anticipated and planned for by the technical community and no one needs to worry about the Internet suddenly breaking. But it does mean that the pressure will continue to build for many networks, necessitating the use of complex and expensive workarounds.

Our advice to network operators is to take stock of their IP resources and to make sure their IPv6 plans are making progress.”

Some big ISPs still have a large stockpile of IPv4s but others that haven’t deployed IPv6 may have to stretch that out by adopting awkward solutions like internet address sharing (Carrier Grade NAT), which can in some circumstances create problems for internet systems that use unique IP addresses to identify, process and or block user activity.

In other cases we have seen some commercial trading of retired IPv4 address space and this is likely to become more common, at least until the day comes that IPv4 can finally be put to bed.

By Mark Jackson
Mark is a professional technology writer, IT consultant and computer engineer from Dorset (England), he also founded ISPreview in 1999 and enjoys analysing the latest telecoms and broadband developments. Find me on X (Twitter), Mastodon, Facebook and .
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19 Responses
  1. Avatar photo boggits says:

    There are a number of techniques that mean you can deploy IPv6 natively and then do IPv4 only where you have too:

    – 464XLAT is already available on many mobile phones but needs your router/device to do the translation on at the edge of the end-user network
    – NAT64 provides a special answer in DNS that are then translated on the border of the network (but can’t cope with literal v4 addresses
    – DSlite also needs the CPE to encapsulate v4 traffic to the edge and was one of the first large scale solutions that tried to avoid full dual-stack

    Dual stack is the way to go to provide 100% coverage but it encourages people to run v4 for far too long… for the hyperscalers there are some impressive traffic stats for networks that have made the transition.

    APNIC provides regular stats https://stats.labs.apnic.net/ipv6/GB?o=cXEw30x1r1 that are based on google ads being served with special code to request unique v4/v6 info

  2. Avatar photo NE555 says:

    To be pedantic, 0:0:0:0:0:ffff:7b55:435a is not an IPv6 address. It’s an IPv4 address, represented in a form which can be passed through an IPv6 API. If you ask a socket to connect to this address, then it will actually use the IPv4 protocol to connect. (7b55:435a = If you see such an address, starting ::ffff:, you are *not* using IPv6.

    Here’s an example of a real IPv6 address: 2001:4860:4860::8888 (that’s Google’s public DNS resolver – the same service as but reachable over IPv6)

    Unfortunately, IPv4 and IPv6 are two completely different protocols which run side-by-side, like ships that pass in the night. They are not directly interoperable.

    Whilst a few large providers(*) offer their services over both IPv4 and IPv6, most do not(**). This means you can’t just switch over your network from IPv4 to IPv6 – you must run both. If you were to build a home network with IPv6 only, you would be locked out from most of the Internet.

    So you still need use of an IPv4 address, directly or indirectly via some sort of NAT – whether it’s NAT44 using a private IPv4 address, or NAT64 using an IPv6 address.

    The end of IPv4 availability from RIPE and other RIRs is going to push out new entrants to the market, and/or force them to buy IPv4 on the secondary markets.

    (*) examples: Google/Youtube, Facebook, Twitter, Cloudflare
    (**) examples include major content providers like bbc.co.uk – and ispreview.co.uk 🙂

    1. Mark-Jackson Mark Jackson says:

      Perfectly fair point NE555, although I wanted to try and showcase the IPv4 to IPv6 transition and so went with that one in order to keep some association between old and new. I thought about adding a little extra explainer in below but felt it may have confused some of the less technically minded readers and got away from the overall point.

    2. Avatar photo Armis2000 says:

      Great timing, NE555!

  3. Avatar photo Optimist says:

    I would like to nominate Virgin Media for 1st prize for kicking the IPV6 can down the road for the longest. Customers have been asking for this on help forum for nearly TEN YEARS. Apart from stating that their network is IPV6 ready yet and regular promises that it will come in “next year” (which never arrives), none of their customers can connect on IPV6. At least they can’t be accused of rushing things!

    1. Mark-Jackson Mark Jackson says:

      Virgin do seem to be ready to go live with this, although their DSlite approach has not been very popular and you could say that right now the shift to DOCSIS 3.1 is taking up a lot of their focus. Plus there are bigger things afoot behind the scenes.

    2. Avatar photo David says:

      Even my EE mobile has been IPv6 for a long time – shows how much they kicked their heels. I believe the IP’s are pretty sticky on the hubs so shouldn’t be a massive problem until it has to be.

    3. Avatar photo A_Builder says:


      I’d be fascinated to hear of the “bigger things afoot”!

      I’m guessing VM are planning to run more fibre to more cabinets so they can run 1G/1G and eventually 10G/10G on the coax?

    4. Avatar photo NE555 says:

      > I would like to nominate Virgin Media for 1st prize for kicking the IPV6 can down the road for the longest.

      I raise you Plusnet, who turned it on in a trial, and then turned it off again.

    5. Avatar photo CarlT says:

      FTTLA isn’t on their radar, Builder. Neither is FDX DoCSIS.

      Upstream can be doubled without deeper fibre.

  4. Avatar photo Joe says:

    I have my doubts about this. As they run out of IPv4 the value increases and a lot of hoarded ipv4s will come onto the market – its happening already

  5. Avatar photo Neb says:

    When do you think the tipping point is for full on conversion to IPv6?
    Next year? When the rest of the world runs out? A special IPv4 holiday where the conversion happens?

    1. Mark-Jackson Mark Jackson says:

      My guess is c.6-10 years (i.e. the point at which IPv4 is no more).

    2. Avatar photo Joe says:

      ISPs will want to see the EOL of their existing home user hardware at least.

    3. Avatar photo NE555 says:

      > When do you think the tipping point is for full on conversion to IPv6?

      It’s looking very much like stalemate at the moment, because you can’t “convert” to IPv6 until all the content is on IPv6; and the content providers mostly don’t bother with IPv6 because they know that 100% of the end-users have IPv4 (with a much smaller percentage also having IPv6).

      End games might be:

      1. Governments around the world pass laws to oblige all Internet content to be published on IPv6 (seems unlikely)

      2. Someone big like Google or Cloudflare decides to offer a free public NAT64 service. End users can then build IPv6-only networks and still reach the rest of the Internet.

      3. An RFC gets written to add 64-bit port numbers to TCP and UDP. NAT+IPv4 becomes a permanent feature of the Internet, and IPv6 withers away and dies

    4. Avatar photo R.M. says:


      In regards to 3., I found this idea by Bill Herren years ago quite interesting. Too bad it never got serious discussion (were there fatal flaws? I don’t know enough to judge)


  6. Avatar photo Dominic Davis-Foster says:

    The flats where I used to live used NAT so that the whole complex had just one IPv4 address. Of course, if one tennant misbehaved and the IP got blocked by a website, so dod everyone else.

    This was just 100 tennants. I’d rather not imagine the mess this approach causes to customers of ISPs stuck on IPv4

    1. Avatar photo Boris Stiffler says:

      I’ll take a bet. Hyperoptic block?

  7. Avatar photo David says:

    So because I am on a mobile provider with IPv6 does this mean that if IPv4 stopped tomorrow I would be ok still? I can see I have one address on each.

Comments are closed

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