I installed an integrated router 1841-ADSL at a customer. It appears to work fine intially but eventually its performance degrades and the customer is unable to reach some websites. If I do an ADSL high speed bandwidth test the speed is fine. I believe the problem is at the ISP, put they are saying everything is ok on their side. Is there a test or debug I can run on the router to prove that the problem is not the router?
I am using pppoe and the DSL bandwidth is 512kbps. The firewall service is enabled on the router.