I use a D-Link 2520Z ADSL modem wired to a WRT120N Linksys router.
For the past week, I have literally seen like 1000 ads on virus removal tool kit, bang your computer is infected, here a girl who wants to meet and what not! Every page I got (heck even on google search results page), I first need to click anywhere the page to open this rdsrv (or adcash) link and only then am I able to click on any valid links.
Thinking this was an issue with my Windows 7 computer - I downloaded all possible anti-virus, anti-malware, anti-spyware software but the thing didn't go away. Selectively deleted every single file (which i thought was suspicious) that got created with the last 10 days and the damn ads will still not go away.
Literally wasted 3 days over this.
Then, i started noticing that my Mac, my android device - every device connected to Wifi had this issue. My phone over 3G didn't get ads!
So I dug things up over the internet and found that something is changing the DNS of my modem and/or router. And bang.. the DNS1 entry on my router and modem were IP addresses of Netherlands!
I did a factory reset of both devices, upgraded their firmwares, changed their login passwords and manually put in Google DNS (188.8.131.52 and 184.108.40.206).. what a relief. All was well for a day, and the next morning I started getting the ads again! My modem's and router's DNS again had a new IP address, this time from Ukraine!
Redid everything and things were fine until the next day.. and I am seeing ads again... on every single page I visit, every single link I click, I see 2 sometimes 3 popups opening up.
What can I do to fix this?
Relevant threads :- https://discussions.apple.com/thread/6987223?start=0&tstart=0