Renesys Corp., a network analyst that has closely followed the Internet problems in Egypt, confirms Twitter reports that the last major public Internet service provider in Egypt is down. 

"They are completely unavailable at present," Renesys says. 

The ISP, Noor, had remained in service after the government sought to block Internet access last week. It has been widely speculated that Noor was allowed to stay up because it connects the stock exchange and Western companies in Egypt.

Although it would seem logical that the government is behind the latest move, it hasn't been independently confirmed whether Noor has been shut down or is simply experiencing technical problems. Some Noor customers in Cairo said they had been told that the ISP was working on repairs and expected to be up in a few hours.

Technolog examined the effectiveness of the government's Net  shutdown here. The BBC, meanwhile, has a fascinating look at how Egyptians are getting around the government blockade using fax machines, ham radio and dial-up modems:

Dial-up modems are one of the most popular routes for Egyptians to get back online. Long lists of international numbers that connect to dial-up modems are circulating in Egypt thanks to net activists We Re-Build, Telecomix and others. ...

The group of internet activists known as Anonymous was also using faxes to get information to students at several schools in the country. Anonymous activists have been faxing copies of cables from Wikileaks relating to Egypt in the hope that the information they contain about the Mubarak regime will be more widely distributed. It is not clear how much impact this is having, however.