The Department of Work and Pensions, UK has an entire /8

Alex Brooks askoorb+nanog at
Tue Sep 18 19:28:06 UTC 2012

On Tue, Sep 18, 2012 at 3:17 PM, Paul Thornton <prt at> wrote:
> On 18/09/2012 15:07, Eugen Leitl wrote:
>> Department of Work and Pensions UK in Possession of 16.9 Million Unused
>> IPv4
>> Addresses
> The only slight snag in his argument is that the addresses are not unused.
> Not announced != Not used.

And for the definitive answer on this block, the official response is: and

>1. We can confirm that the address block is assigned to the DWP.
>2. In principle, none of the address space is exposed to the public Internet.
>There may be a very small number of addresses that have been exposed for
>specific purposes, but certainly no significant block of addresses is visible
>from the public Internet.
>3. The address space is already shared across government. We have used or
>allocated approximately 80% of the address space, and have earmarked the
>remaining space for use within the proposed Public Services Network (PSN).
>The PSN is building an Internet for government, and the DWP address space
>is a key building block for delivery of this.
>4. DWP have no plans to release any of the address space for use on the public
>Internet. The cost and complexity of re-addressing the existing government
>estate is too high to make this a viable proposition. DWP are aware that the
>worldwide IPv4 address space is almost exhausted, but knows that in the
>short to medium term there are mechanisms available to ISPs that will allow
>continued expansion of the Internet, and believes that in the long term a
>transition to IPv6 will resolve address exhaustion. Note that even if DWP were
>able to release their address space, this would only delay IPv4 address
>exhaustion by a number of months.

And for to the response from the Ministry of Defense is:

>I can confirm that the IPv4 address block about which you enquire is assigned to and
>owned by the MOD; however, I should point out that within this block, none of the
>addresses or address ranges are in use on the public internet for departmental IT,
>communications or other functions.  To date, we estimate that around 60% of the IPv4
>address block has been allocated for internal use. As I am sure you will appreciate, the
>volume and complexity of the Information Systems used by the Armed Forces supporting
>military operations and for training continues to develop and grow.    We are aware that the
>allocation of  IPv4 addresses are becoming exhausted, and the issue has been recognised
>within the Department as a potential future IS risk.
>In summary, therefore, we are unable to consider releasing parts of the address block that
>has been allocated to the UKMOD for reassignment to non-UK Government organisations.

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