Some AT&T customers are being affected by a failure in the carrier's DNS (Domain Name System) servers that began Wednesday morning.
Initial reports indicate the failure is hitting companies across the U.S., but few details are immediately available.
"We are currently experiencing DNS issues which could affect DMS (Digital Media Solutions) clients who also host their DNS with ATT," the carrier said in a short message posted to a service status on its Managed Services website. "Our Network Operations team is aware of the problem and is working the issue"
The status message said there is "no estimated time" for restoring the service.
AT&T did not respond to several requests for comment.
DNS is responsible for converting human-friendly domain names into the numeric IP (Internet protocol) addresses that computers use to route data. When it fails, computers are unable to route data to its intended destination, even though the destination server remains online and accessible."Our highest level of technical support personnel have been engaged and are working to mitigate the issue," AT&T said.
"We got our first report of problems at 6:31 a.m. Pacific time," said Daniel Blackmon, director of software development, at Worldwide Environmental Products. The company tests vehicle emissions and has remote units deployed that report back to central servers.
"The problems mean none of the equipment we have in the field can contact our servers, and there is a limit to the amount of information they can hold offline."
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is firstname.lastname@example.org