Microsoft has offered to pay $7.5m (£4.7m) for bankrupt telecoms firm Nortel for its web addresses.

The 666,624 IP version 4 web addresses were put up for auction as part of the selloff of Nortel’s assets.

The deal is yet to be complete while Microsoft waits for it to be approved by Delaware bankruptcy court where details of the sale are being held.

If the Microsoft-Nortel deal goes through, Microsoft will get hold of 470,016 of the IP addresses with immediate effect, but will wait on the remaining 196,608 as former customers of Nortel are moved to other telecoms firms.

The deal values the IP version 4 address blocks at $11.25 (£7) each; more than the price many firms charge for a .com domain.

IP addresses are used to identify individual computing devices on the internet.  IP version 4 allows a maximum of approximately 4.3 billion devices.

The rapid growth in personal computers, smartphones and other internet connected devices means that addresses are rapidly running out.  All of them are expected to be used up by the end of 2011.