Friday, 27 March 2015

Changing your DNS Servers - Problems Accessing The Internet Due To DNS Issues Then Read This!

Changing your DNS Servers

Are You Having Problems Accessing The Internet Due To DNS Issues Then Read This!

By Strictly-Software

Sometimes I get problems at home when my laptop cannot connect to the Internet due to DNS issues.

This happens quite regularly and my ISP is Virgin Media.

If you really don't know what you ISP is then go to this site whatismyipaddress.com.

Also you may get issues when your ISP blocks certain sites that you want to visit e.g. The Pirate Bay or other torrent sites or information clearing houses or anti establishment websites.

Therefore if you are getting DNS issues then you should have a look at some of the various solutions below to see if any are suitable for your needs.

1. Default Set-Up

Your system will usually be set up by your ISP to use DHCP (Dynamic Host Configuration Protocol) which from the article about DHCP says that your computer assigns a different IP address automatically every time you access the Internet.

However my settings have been on DHCP for years and I haven't noticed my IP address change except for a couple of times which can be very annoying. Especially if you have firewall exceptions and programs on other servers like Fail2Ban or DenyHosts to prevent you being banned (SSH, TCP/IP),

The reason your IP address might change is down to DHCP which is used to issue unique IP addresses to computers accessing the ISP as well as automatically configuring other network information on your computer.

As we haven't moved to IPv6 yet and we don't have enough IPv4 addresses for every single device accessing the internet an ISP will share IP addresses as well as using proxy servers or gateways to allow your device, whether it be a phone, tablet, TV, laptop, PC or car, to access the internet.

However be careful before changing your DHCP settings as they could cause problems especially if you are on a shared network.

In most homes and small businesses, the router acts as the DHCP server.

However on large networks, a single computer might act as the DHCP server and changing your DNS settings could cause problems especially if you use internal networks to access websites.

For example at my company I have test sites on internal IP addresses and changing the DNS addresses prevents me from accessing those sites.

You can read more about DHCP here.

However whilst the article says that in most cases a new IP address is assigned to your device every time you connect to the network I find my computers IP address stays the same for quite a while and only changes every four or so months.

If you don't know your IP address then you can easily check your IP address from your own PC without having to open a webpage. Or you can easily use the Internet and run a search for "What is my IP".

If you would like a little script that you can run from the command line or at the click of a button to get a popup with your external IP address then you can read this article on obtaining your IP address from your computer without using a browser.

2. Checking your DNS address from the Command Prompt

You can check your current DNS settings from the command prompt with ipconfig /all which will show you all your network connections and DNS details.

I have shown you my own home computer settings and you can see the DNS settings I am using at the bottom are Google's.


C:\Users\rreid>ipconfig /all

Windows IP Configuration

   Host Name . . . . . . . . . . . . : stard0026w7
   Primary Dns Suffix . . . . . . . : metal.strictly-software.com
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : metal.strictly-software.com

Ethernet adapter Local Area Connection:

   Connection-specific DNS Suffix . : metal.strictly-software.com
   Description . . . . . . . . . . . : Broadcom NetLink (TM) Gigabit Ethernet
   Physical Address. . . . . . . . . : D4-BE-D9-95-40-DB
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::fc53:2287:bb47:b8a9%11(Preferred)
   IPv4 Address. . . . . . . . . . . : 10.0.7.79(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : 23 February 2015 17:06:21
   Lease Expires . . . . . . . . . . : 19 March 2015 15:49:01
   Default Gateway . . . . . . . . . : fe80::20c:29ff:fe77:3876%11
                                                   10.0.7.249
   DHCP Server . . . . . . . . . . . : 10.0.7.244
   DHCPv6 IAID . . . . . . . . . . . : 248823513
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-02-22-03-D4-BE-D9-95-40-DB

   DNS Servers . . . . . . . . . . . : 8.8.8.8
                                                  8.8.4.4
   Primary WINS Server . . . . . . . : 10.0.7.1
   NetBIOS over Tcpip. . . . . . . . : Enabled

3. Obtaining Different DNS Settings


So one of the solutions to this problem is to change your DNS server IP addresses to public DNS Servers like Googles free addresses 8.8.8.8 and 8.8.4.4 or you can use many others including opendns.com.

This provides security at the DNS level that protects your computer from malware and other threats including probes and hacks which could save you without installing any further software.

If you are a business you have to pay but for personal use you don't and can just use these addresses 208.67.222.222 or 208.67.220.220.

Read more about opendns here.

You can find a big list of other DNS server IP's to use here.

Some of them include:

ProviderPrimary DNS ServerSecondary DNS Server
Level3209.244.0.3209.244.0.4
DNS.WATCH84.200.69.8084.200.70.40
Comodo Secure DNS8.26.56.268.20.247.20
OpenDNS Home208.67.222.222208.67.220.220
DNS Advantage156.154.70.1156.154.71.1
Norton ConnectSafe199.85.126.10199.85.127.10
GreenTeamDNS81.218.119.11209.88.198.133
SafeDNS195.46.39.39195.46.39.40
OpenNIC107.150.40.23450.116.23.211
SmartViper208.76.50.50208.76.51.51
Dyn216.146.35.35216.146.36.36
FreeDNS37.235.1.17437.235.1.177


4. Changing DNS Settings


Every computer will be slightly different and you and you can search Google to find out how to do it on your computer, tablet, phone or even your smart TV.

This example is for Windows 7 but it not so different for other Windows machines:
  • Go to Control Panel and select Network and Sharing Center.
  • Select Change Adaptor Settings.
  • Select the network connection you want to change LAN or WIFI.
  • The panel will open showing you your connection details.that shows the network connection you want to change e.g LAN or WIFI.
  • Scroll down to Internet Protocol Version 4 (TCP/IPv4) (leave IPv6 for later!),
  • Click on that row then Properties,
  • In the bottom half are the DNS settings. Your ISP will most likely have ticked "Obtain DNS Server address automatically" so de-select that,
  • Select "Use the following DNS server addresses" and then enter first your preferred IP address e.g 8.8.8.8 and then in the alternate DNS server put 8.8.4.4
  • Hit OK and the settings should be saved. Test it by trying to get to a web page. If you can access a webpage by the
  • If you are not sure the DNS settings are being used then go to point 2 and check from the command prompt that your DNS settings have been changed.


A good idea might be to set your DNS up so that it uses Googles primary IP 8.8.8.8 for the preferred server and then the OpenDNS IP 208.67.222.222 for the Alliterate DNS Server.

E.G Mix and Match in-case one of the servers goes down..

5. Other Quick Options To Try

Other options you can try to attempt to sort your WIFI out without getting "techie" include just turning off WIFI fr a 30 seconds then back on.

Or you could turn your machines Airplane mode on and waiting a minute before turning it back off.

Turning your router off by unplugging it or taking the power cable out of the back of it. Wait a good 5 minutes then turn it back on.

Using the computers online diagnostic tool to test why your system is down. If it says DNS problems then this article might be for you.



6. Conclusion

Remember all modern devices like phones, tablets and even Smart TV's can connect to the internet and they all have options to change their DNS settings if you are having problems.

Also you must be careful if you are on a work computer as changing your DNS might not be a good idea as you could have internal routing going on to locally hosted sites on the companies internal network.

Therefore changing them might prevent you from viewing some websites (especially dev/demo sites).

You can always test by checking an internal site to see if you get a workable screen or just a "cannot connect" message.


© 2015 Strictly-Software

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