Alexander is also the director of the National Security Agency and will now head the newly-created Cyber Command at the NSA's headquarters in Fort Meade, Maryland.
The Cyber command was conceived under the Bush administration to counter threats from Russian, Chinese and North Korean hackers who have increasingly taken to cyber attacks on US based companies and entities. Chinese and Russian hackers have been consistently targetting US sites and hacking their military sites.
Computer search giant Google recently reported that Chinese hackers had managed to hack into some of its subscribers' email accounts. In 2007, Russian hackers have been accused of a massive cyber assault on Estonian sites.
The Pentagon has said that the Cyber Command will defend specific Department of Defence networks and ensure US freedom in cyberspace.
Former Bush administration terrorism advisor Richard Clarke's book Cyber War cautions against the cyber equivalent of 9/11. Clarke argues that China has down sized its conventional forces and invested heavily in its cyber-forces could fare better against the US.
Even the ultra-reclusive North Koreans have been bolstering their cyber capabilities, which Clarke believes is the harbinger of a ground invasion of South Korea. The utility of a cyber attack during conventional attacks can been seen from when the Israelis hacked into Syrian Air Force system and took over their air defence systems, when its jets attacked a suspected nuclear facility.
Alexander's appointment seems to show that US is finally waking up to the reality of cyber warfare and taking this threat seriously. As Clarke warns the Americans are seriously behind in this field and their ability to defend their networks is not very good. Some liberals have said that the formation of a cyber war command is the beginning of the militarisation of cyberspace.
Image: General Keith Alexander testifying before a Senate committee in Washington.
Photograph: Larry Downing/Reuters