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The University of Houston went one step further and made sure that its call manager and its entire VOIP network aren't directly accessible from the Internet. The school has put its IP PBXs in a different domain than its other servers and has limited administration access to the servers.
"As a university, the potential for being hacked or coming under a denial-of-service attack is a huge concern for us," says Charles Chambers, the university's manager of network planning and development
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