It could be most likely the backup to your ISP's DNS. Settings always have two for redundancy & they can set them if you leave it up to them (meaning the second DNS spot blank).
I would almost never use an ISP's DNS (bc some sell that info to ad co's) and definitely don't leave the DNS up to whatever free wifi network you attach to (bc they can sell it too) - it's like asking a stranger for directions you don't trust and they could even put up a sign at the place and put an employee with a badge on to fool you... With that said, here's what I use:
Personally, I use FoolDNS bc they block ads, trackers and viruses: http://www.fooldns.com/fooldns-community/english-version/
I set up ComodoDNS on family computers bc they block malicious content: https://www.comodo.com/secure-dns/switch/
I second Namecoin. Comodo is also good. Although I've been using my VPN's DNS for a while now (requires a subscription though).
If it weren't for the fact it was based in Australia, and has a higher ping as a result, I would probably still be using ClouDNS, as it supports DNSCrypt, DNSSec, and Namecoin resolution all in one.
Try this: https://www.comodo.com/secure-dns/
It is free, and requires no additional hardware or software.
All you have to do is go into her internet settings, go to DNS, and paste in those two addresses. Then, theoretically, when she goes to a bad site, it will block it and/or she will get a warning.
Essentially, you are trading some privacy in exchange for security. Although, I wouldn't be too worried, as Comodo seems to be a pretty reputable company.
ctrl+shift+esc directly opens task man, windows+r opens the 'run' dialogue from which you can launch system utilities and programs. Learn how to use diskpart (win) and gparted (Linux). If you can't get something to work like driver install or program removal try safe mode. Have a proper firewall and learn how to manage it so that your system is secure. RUN YOUR SECURITY CHECKS AND UPDATES (one or more times per week). Ctrl+shiift+t open the tab you just closed on accident. Use a secure DNS to avoid page redirects and other sneaky internet pages
edit: spelling, a word
If you really need something:
https://home.sophos.com/en-us/download-mac-anti-virus
Edit: Use an Adblock as well, Ublock Origin. If you’re really worried, change the DNS to a secure DNS like Comodo
Not necessarily more secure, but apparently some internet providers in the US occasionally "hijack" DNS requests to serve ads and the like.
Another possible set of DNS servers are Comodo Secure DNS: https://www.comodo.com/secure-dns/
That actually uses a blacklist of DNS entries leading to malicious sites that will be redirected to a warning page if accessed.
I use this myself at home.
Change your DNS (on PC or Router) to use COMODO or NORTON, free service for home users to block bad websites.
> As a leading provider of computer security solutions, Comodo is keenly aware of the dangers that plague the Internet today. SecureDNS helps users keep safe online with its malware domain filtering feature. SecureDNS references a real-time block list (RBL) of harmful websites (i.e. phishing sites, malware sites, spyware sites, and parked domains that may contain excessive advertising including pop-up and/or pop-under advertisements, etc.) and will warn you whenever you attempt to access a site containing potentially threatening content. Additionally, our 'name cache invalidation' solution signals the Comodo Secure DNS recursive servers whenever a DNS record is updated - fundamentally eliminating the concept of a TTL. Directing your requests through highly secure servers can also reduce your exposure to the DNS Cache Poisoning attacks that may affect everybody else using your ISP.
A quick google search gave me these: Comodo Secure DNS Norton ConnectSafe
Comodo seems a good option to me, seeing as they provide several node servers placed all around the world.
I haven't had a problem combining Comodo Antivirus with Waterfox. But I don't use the Firewall.
Isn't there an option to use Comodo's "safe" DNS, replacing the normal one with a Comodo one? Maybe Waterfox noticed and thinks it is a hacker of some sort. So it displays the error.
Maybe try to turn it off if it is turned on.
Here is a link to what I mean: https://www.comodo.com/secure-dns/
Personally I'd reccomend OpenDNS unless you want to tell Google EVERY website that you go to and after all the barstards know more about you than the Stasi or the KGB could ever have dreamed of.
Also Comodo the antivirus people do one as well.
OpenDNS IPv4 addresses
208.67.222.222 (resolver1.opendns.com) 208.67.220.220 (resolver2.opendns.com) 208.67.222.220 208.67.220.222
(any two lines will do)
IPv6 addresses[7]
2620:0:ccc::2 2620:0:ccd::2
Comodo 8.26.56.26
8.20.247.20
I can't find their IPv6 IPs
Changing DNS provider guide
https://www.comodo.com/secure-dns/switch/windows_vista.html
The Vista guide also works for Win 7 and probably 8+10 as well theirs also guides there for XP and OSX.