Hit with DNS Changer shutdown? Here’s what to do.

MICHEL RUBINEL/AFP/Getty Images - A woman looks at the FBI Internet site page dedicated to the DSN Malware on July 9, 2012 in Paris.

Monday marks the day that the Federal Bureau of Investigation rips off the bandage it put in place to redirect computers infected with the DNS Changer virus — meaning that thousands of computer users in the United States could now be struggling to get on the Internet.

Nicknamed the “Internet doomsday” virus, DNS Changer is essentially a piece of malware that mucks with the way that computers ensure they’re accessing the Web sites correctly. To be clear: this shouldn’t affect the actual architecture of the Internet or its ability to run. This isn’t a planned attack. In fact, it’s just the end of a contract.

More tech stories

Parking doesn’t have to be a hassle

Parking doesn’t have to be a hassle

Meet the man who wants to make parking in a garage as fun as riding in an Uber.

Big data: A double-edged sword

Big data: A double-edged sword

New information will improve our health and prevent crimes, but uncover skeletons and hurt privacy.

White House updating online privacy policy

White House updating online privacy policy

A new Obama administration privacy policy explains how the government will gather the user data of online visitors to WhiteHouse.gov, mobile apps and social media sites, and it clarifies that online comments, whether tirades or tributes, are in the open domain.

Since the FBI took down the virus’s authors in November, the agency has had a safety net of servers to handle traffic from infected machines in order to give folks time to find and clear out the malicious program. The contract on that safety net ran out at 12:01 a.m. on July 9.

Ahead of that deadline, there’s been a big push to let folks know about the virus, which initially redirected infected users’ Web traffic to fake or counterfeit servers. Even Facebook and Google have been notifying users that their Mac or PC computers may be infected. But even with those efforts, FBI spokeswoman Jenny Shearer told ABC News Friday that there were still around 46,000 U.S. users who would lose connectivity.

If you’re one of those folks — maybe reading this from your phone because your computer won’t connect — there’s still no reason to panic. It may take a little while to get things back up and running, but you won’t be cut off from the Internet forever. For any person having trouble getting their computer back into fighting form, the FBI also recommends that you call your Internet service provider to let them know you’re having problems.

The first thing to do is to back up your important files onto an external hard drive to make sure that your essential items are safe. In some cases, you may have to reinstall your operating system to completely to get rid of the persistent virus, so having a second copy of your most important items is key.

From there, you’ll have to run a scan. There are plenty of virus tools out there that can get rid of the virus — but many of them require, well, a download. These include programs such as Windows Defender Offline, MacScan and PowerEraser: for a complete list go to the DNS Changer Working Group Web site.

If you do have these tools on your computer already, you can run a scan to remove the virus. Otherwise, call your Internet service provider for their best advice on what to do next.

Once your scan is done, you may also have to reset your router or modem settings to get back up to speed. The OpenDNS group has a good explainer on how to set your own DNS settings, though users may want to contact their Internet providers to get instructions on how they want customers to have their settings configured.

Related stories:

What the ‘Internet doomsday’ virus is and how to fix it

Ideas@Innovations: The ‘doomsday’ virus and the tragedy of the Internet commons

Poll: personal vulnerabilities online

Read what others are saying