Knowledgebase : CloudFlare, DNSs, Domains

In case you WordPress admin and/or login pages got locked-in and the issue is not with plugins, double-check if if your domain is not using CloudFlare as proxy.

As of November 2016 CloudFlare changed its IPs. So, either exclude your admin/login pages from CloudFlare or add new CloudFlare IPs to your .htaccess

(IPv4)

allow from 199.27.128.0/21
allow from 173.245.48.0/20
allow from 103.21.244.0/22
allow from 103.22.200.0/22
allow from 103.31.4.0/22
allow from 141.101.64.0/18
allow from 108.162.192.0/18
allow from 190.93.240.0/20
allow from 188.114.96.0/20
allow from 197.234.240.0/22
allow from 198.41.128.0/17
allow from 162.158.0.0/15
allow from 104.16.0.0/12
allow from 172.64.0.0/13

(IPv6)
allow from 2400:cb00::/32
allow from 2405:8100::/32
allow from 2405:b500::/32
allow from 2606:4700::/32
allow from 2803:f800::/32
allow from 2c0f:f248::/32
allow from 2a06:98c0::/29

More in CloudFlare IPs: How do I whitelist CloudFlare's IPs in .htaccess?

The UltraDNS Directory Services Platform currently consists of a mesh of fifteen (15) globally synchronized DNS network nodes located on five (5) continents with DNS Advantage equipment at the majority of them. Their locations are as follows:

http://www.dnsadvantage.com/dnsadv/node_locations.html

It takes minutes to move to Neustar DNS services.

156.154.70.1

and

156.154.71.1
Доменный алиас (доменный синоним, domain alias, domain aliasing) - это способ сопоставить два или более разных доменных имени одному и тому же содержимому, одному и тому же сайту, т.е. использование альтернативных доменных имен для ссылки на одну и ту же область памяти сервера. 
 При наборе такого доменного имени пользователь видит в адресной строке своего броузера каждый раз именно тот url, который он набрал. Например, для одного и того же сайта можно зарегистрировать несколько доменов в различных доменных зонах - yourdomain.ru, yourdomain.com и yourdomain.info. При этом, какой бы из этих адресов посетители не набрали, они попадут на один и тот же сайт. 

The following article explains how to flush a computer's DNS cache.

When a computer visits a website for the first time, it stores the website's DNS information in cache.
The next time the computer visits a website, it looks in the cache to see if the website's information is present to use.
This can cause problems if the website's DNS information has changed since the computer's last visit.
Flushing the cache removes all the information stored in cache, forcing the computer to find the new DNS information for the website.

To flush DNS for a computer running Windows, please follow these steps:
==================================================+
1.On your local machine, open a command prompt.
2.Within the prompt, type ipconfig /flushdns.


To flush DNS for a computer running Mac OS, please follow these steps:
==================================================+
1.On your local machine, open a terminal window.
2.Within the prompt, type lookupd -flushcache.

To flush DNS for a computer running Mac OS 10.5 Leopard, please follow these steps:
==================================================+
1.On your local machine, open a terminal window.
2.Within the prompt, type dscacheutil -flushcache.

Source:
http://www.hosting.com/support/info/flushdns/
Google DNS vs OpenDNS: Google Rocks for International Users

Slow DNS resolving is one of the major causes of browsing slowdowns.

The DNS services provided by the ISPs were often crappy and erratic and OpenDNS had emerged as the de-facto alternative.
OpenDNS was not without its faults.
Though it was rarely erratic, the performance was not blazing fast.
Also if OpenDNS did not find a site, it redirected the user to a generic search page.
This was not good user experience.
Another alternative was the DNS server 4.2.2.2 (owned by Level 3 I believe).
But this server was not that fast outside United States.

Google DNS consistently outperformed both OpenDNS and Level 3. For Americans the Level 3 server (4.2.2.2) might offer as good performance as Google. But if you are living outside US and you care about your browsing experience you should switch now :). The results are below

Source and Read more here
http://www.manu-j.com/blog/opendns-alternative-google-dns-rocks/403/

Also visit
Using Google Public DNS
http://code.google.com/speed/public-dns/docs/using.html

Public DNS Servers
http://www.topbits.com/public-dns-servers.html

OpenDNS
http://www.opendns.com/about/overview/

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