Need Firefox add on that checks for Safe websites?

The ones I use personally are Web Of Trust add on:

https://addons.mozilla.org/en-US/fir...browsing-tool/ - notifications.

BitDefender TrafficLight:

https://addons.mozilla.org/en-US/fir.../trafficlight/ - also strips harmful elements out of web pages allowing you to visit them.

Metascan Online (requires API) but is free.

Metascan Firefox Add On released

Then although it's not a Firefox Add On you might as well use a secure DNS Lookup Server that blocks access to malicious websites no matter what browser you use.

https://www.comodo.com/secure-dns/switch/

Also check out: https://addons.mozilla.org/en-US/fir...-link-checker/

unifex said:

Callender said:

Then although it's not a Firefox Add On you might as well use a secure DNS Lookup Server that blocks access to malicious websites no matter what browser you use.

https://www.comodo.com/secure-dns/switch/

This is a question of trust, isn't it? How do I know that this particular company is more trustworthy than my ISP?

I guess it depends on your ISP. If they provide secure DNS servers that block known malware sites and that cannot suffer from DNS Poisoning that can affect every user using the same ISP.

If you want to be paranoid look at DNS Crypt and More on DNS Crypt

The suggestion to change to something else was aimed at the original poster who obviously experienced problems when using his ISP's DNS Lookup Server.

EDIT: I was getting threads mixed up. See: Pages take a long time and unresponsive-all browsers

Personally I tend to alternate between a few DNS Lookup Servers - switching whenever I think that there might be a problem.