Network problems at one of the Washington area's largest Internet service providers have prevented some subscribers from checking their e-mail accounts and accessing Web sites.
Comcast Corp. said the intermittent service interruptions affected service to cable Internet service subscribers throughout the country. Spokeswoman Jeanne Russo declined to say how many customers were having problems locally.
Russo said the interruptions began April 7 when Comcast started upgrading its domain name system (DNS) computers -- the machines that help direct Internet traffic by translating Web site names into numeric Internet addresses.
Additional interruptions in the Comcast network occurred on Tuesday, Wednesday and Thursday evenings. In each case, Russo said the problems lasted between three to five hours. She added that the company would issue credits to any customers who had problems as a result of the outages.
"We have put a fix in place to address our DNS issues and believe it to be a success," Russo said.
The Philadelphia-based company has about 7 million Internet subscribers nationwide; the company declined to say how many Internet subscribers it has in the Washington region.
Comcast subscribers from around the country posted complaints at several Internet message boards. At BroadbandReports.com, which maintains a separate forum specifically for Comcast users, hundreds of users information and tips on how to work around connectivity problems.
Most customers who experienced problems technically had Internet access but could not browse the Web or send e-mail because Comcast's servers were not routing Internet traffic. Some users posted to message boards saying they had success in browsing the Web after configuring their computers to point to DNS servers operated by other Internet service providers.
Comcast does not advise its customers to switch their DNS settings, Russo said.
Mike Hirsch, a webmaster for Wicomico County, Md., Department of Recreation, Parks & Tourism, said he helped at least 15 local residents reconfigure their service, including two people who were trying to file their taxes online.
"I knew from reading the message boards about this online that it's just not worth it for people to call Comcast about this," Hirsch said. "Even if they do get through, all the company is going to say is, 'We've got a problem and we're trying to fix it.' "
Andrew John, 43, who runs a home remodeling business in Lancaster, Pa., said he decided to sit tight and do nothing the first time he found he couldn't access the Internet through his Comcast account. Now, after experiencing a third outage, John said he may try to tinker with his settings.
"My connection has been down for 80 percent of the night for the past two days," John said in an telephone interview. "It's a real pain."
Krebs is a staff writer for washingtonpost.com.