Can not reach some web sites

[A.J. Bonnema]

On 09/19/2014 01:24 PM, Ed Greshko wrote:
> On 09/19/14 19:20, Steve Searle wrote:
>> Around 12:13pm on Friday, September 19, 2014 (UK time), A.J. Bonnema wrote:
>>
>>> Hallo,
>>>
>>> I have been experiencing a problem with reaching some websites. Example:
>>> I can not reach http://en.wikipedia.org.
>> This won't fix it, but might help with the diagnosis.
>>
>> en.wikipedia.org resolves to 91.198.174.192
> Not everywhere in the world....
>
> [egreshko at meimei ~]$ host en.wikipedia.org
> en.wikipedia.org has address 198.35.26.96
> en.wikipedia.org has IPv6 address 2620:0:863:ed1a::1
>
>
>> Try to ping this:
>>
>>    $ping -c4 91.198.174.192
>>
>> If this works try to access the page using this ip address, i,e, put
>> http://91.198.174.192 as the address you want to go to into your
>> browser.
>>
>> If this works it shows the problem is with the nameserver you are using.
>>
>> Cheers
>>
>> Steve

Ed and Steve: thanks to your input I found the culprit. I was indeed 
able to find the site through IPV4 IP address, but not through the name. 
So I disabled IPV6 using the command from Ed, and low and behold: there 
is it was, case solved.

However, what baffles me is why ipv4 and ipv6 can be active from Windows 
and work, while from linux I have to disable ipv6! Both machines work 
from the same network / subnet and reach the internet through the same 
router (fritz.box) and use the same dns.

One of the supporters of my ISP suggested I clean the dns cache. Would 
any of you know how to do this from Fedora? And whether it would help?

Kind regards, Guus.