But the NorTel network was not structured that way. What the IS hackers found was a network with no hierarchy. It was a totally flat name space. And the network was weird in other ways too. Every computer system on it contained the address of every other computer, and there were more than 11000 computers in NorTel's worldwide network. What the hackers were staring at was like a giant internal corporate Internet which had been squashed flat as a pancake. Mendax had seen many flat structures before, but never on this scale. It was bizarre. In hierarchical structures, it is easier to tell where the most important computer systems--and information--are kept. But this structure, where every system was virtually equal, was going to make it considerably more difficult for the hackers to navigate their way through the network. Who could tell whether a system housed the Christmas party invite list or the secret designs for a new NorTel product? The NorTel network was firewalled, which meant that there was virtually no access from the outside world. Mendax reckoned that this made it more vulnerable to hackers who managed to get in through dial-ups. It appeared that security on the NorTel network was relatively relaxed since it was virtually impossible to break in through the Internet. By sneaking in the backdoor, the hackers found themselves able to raid all sorts of NorTel sites, from St Kilda Road in Melbourne to the corporation's headquarters in Toronto. It was fantastic, this huge, trusting network of computer sites at their fingertips, and the young hackers were elated with the anticipation of exploration. One of them described it as being `like a shipwrecked man washed ashore on a Tahitian island populated by 11000 virgins, just ripe for the picking'. They found a YP, or yellow pages, database linked to 400 of the computer sites. These 400 sites were dependent on this YP database for their password files. Mendax managed to get root on the YP database, which gave him instant control over 400 computer systems. Groovy. One system was home to a senior NorTel computer security administrator and Mendax promptly headed off to check out his mailbox. The contents made him laugh. A letter from the Australian office said that Australia's Telecom wanted access to CORWAN, NorTel's corporate wide area network. Access would involve linking CORWAN and a small Telecom network. This seemed reasonable enough since Telecom did business with NorTel and staff were communicating all the time. The Canadian security admin had written back turning down the request because there were too many hackers in the Telecom network. Too many hackers in Telecom? Now that was funny. Here was a hacker reading the sensitive mail of NorTel's computer security expert who reckoned Telecom's network was too exposed. In fact, Mendax had penetrated Telecom's systems from NorTel's CORWAN, not the other way round.