The internet's master address books are being updated to include records in IP version 6 (IPv6), a new format which forms part of a major overhaul of the net's core address system.

PCs translate the words we type in internet addresses into a string of numbers from the net's master address books to help us navigate our way around the web. The majority of these numerical codes are written in IPv4 but under this version the pool of unallocated addresses looks set to run out by 2011.

However, by introducing addresses written in IPv6, an effectively inexhaustible pool of addresses becomes available. The new addresses will be introduced to the root servers for the net today.

According to Paul Twomey, president of Icann, which oversees the addressing system, the total of unallocated addresses is rapidly running out putting pressure on people to convert to IPv6.

"Just 14 per cent of the unallocated addresses out of the whole pool for version 4 remain," he said.

Jay Daley, technology director at Nominet, which oversees .uk domains, said that for a long while, consumers will only see minimal effects.

"Eventually home routers may have to be upgraded or swapped so they can use the longer addresses," he added.