TalkTalk and Post Office broadband customers have lost internet access as a result of a cyber attack.
On Sunday November 27th, cyber attackers used malware to target several types of router, including the Zyxel AMG1302.
About 100,000 Post Office customers have been affected, while the number of TalkTalk subscribers to be hit has not yet been confirmed.
In a statement, the Post Office stressed that while the attack did create service problems, no personal data or devices were compromised.
"We have identified the source of the problem and implemented a resolution which is currently being rolled out to all customers," it said.
"We would like to apologise to any customers who have been experiencing issues with their Post Office broadband service. For those customers who are still having problems we are advising them to reboot their router."
The Post Office added that it constantly reviews its systems and processes to protect customers against this type of incident.