Santa Rosa-based internet service provider Sonic is suffering from a distributed denial of service attack that's causing connectivity problems for its customers in San Francisco, and elsewhere around the Bay Area.

It’s unclear how widespread the outage is, but several San Francisco residents have tweeted that they are experiencing connectivity issues in Hayes Valley, the Lower Haight and the Richmond District, among other neighborhoods.

A distributed denial of service attack uses a network of often co-opted machines to flood the target with dummy requests in an attempt to overload a network.

Details about the attack were not immediately available, but according to a short blog post the company said that as of 12:30pm on Tuesday, “the Sonic network is experiencing reachability issues to the outside world. A large DoS attack is the suspected cause, but we are still working to identify and mitigate the problem ASAP.”

A Sonic support staffer told this reporter that as of 1:30pm there was no estimate about when connectivity would be restored.

"Everyone on our systems and engineering teams is working to get the situation resolved as soon as possible," said Sonic spokesperson Tara Sharp. "Some of the smartest people in the internet business are working to resolve this immediately."

Update: Sonic reports that as of 3:42pm, the company believes that service is restored.

The company has been drive to expand its offerings in San Francisco, and has been rolling out its Gigabit Fiber internet in the Richmond District and the Sunset.

Small and local internet providers scored a legislative victory in December of 2016, when the Board of Supervisors passed an ordinance that requires landlords to allow any state-accredited access to buildings.

The ordinance was, in part, a response to reports that landlords earn kickbacks from big providers in exchange for not giving tenants a choice of internet provider.

We will update the story as more information becomes available.