He said VeriSign’s DNS computers now get 30 billion queries a day, compared with 1 billion in 2000, while security exploits have grown eightfold over that period. In February, the company announced Project Titan, an initiative to expand the capacity of its systems tenfold by 2010 — to 4 trillion queries a day. The extra capacity is needed to respond to any unusual surges from legitimate demand, as well as to overcome any denial-of-service attacks, in which hackers try to overwhelm the systems with fake traffic.

The price hike does not require any regulatory approval. Under a deal reached in November with the US Commerce Department and the Internet Corporation for Assigned Names and Numbers, the nonprofit group that oversees Internet addressing policies, VeriSign could increase “.com” prices as much as 7 per cent during four out of the six years the contract is in effect. The company may also raise fees during the other two years under limited conditions. VeriSign also runs the computers that list all 266 domain name suffixes, such as “.fr” for France and “.biz” for businesses. Fees for other domains aren’t going up, but VeriSign could use the “.com” and “.net” revenue to subsidise upgrades. VeriSign shares increased 1 cent to close at $25.65 Thursday on the Nasdaq Stock Market.