There are a number of problems that can cause your computer to be unable to resolve anything:

  • The DNS settings in your computer could be misconfigured
  • The network settings in your computer could be misconfigured
  • Your DNS servers could all be broken
  • The network between your computer and your DNS servers could be down
  • A firewall could be blocking your DNS requests, or the DNS replies

Troubleshooting Being Unable to Resolve Anything

The first thing to do when troubleshooting the problem of being unable to resolve anything is to determine if IP networking, other than DNS, is working properly.

To test networking, ping an IP address across the Internet that you recognize and that you are certain works normally.

C:>ping 199.196.144.95

Pinging 199.196.144.95 with 32 bytes of data:

Reply from 199.196.144.95: bytes=32 time=41ms TTL=243
Reply from 199.196.144.95: bytes=32 time=42ms TTL=243
Reply from 199.196.144.95: bytes=32 time=36ms TTL=243
Reply from 199.196.144.95: bytes=32 time=41ms TTL=243

Ping statistics for 199.196.144.95:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 36ms, Maximum = 42ms, Average = 40ms

If this works, then at least some networking is working for you and you have a DNS problem. If this fails, then your network is not working.

Let's try to do a DNS name resolution and see if it works: C:>nslookup
Default Server: ns2.attbi.com
Address: 216.148.227.68

> www.byteguide.com
Server: ns2.attbi.com
Address: 216.148.227.68

Non-authoritative answer:
Name: www.byteguide.com
Address: 66.37.153.76

If this works, then you can at least resolve some things.

If this fails, then you might try to use a different DNS server. In this example, we borrow DNS service from GTE Internet:

C:>nslookup
Default Server: ns2.attbi.com
Address: 216.148.227.68

> server 4.2.2.2
Default Server: vnsc-bak.sys.gtei.net
Address: 4.2.2.2

> www.byteguide.com
Server: vnsc-bak.sys.gtei.net
Address: 4.2.2.2

Non-authoritative answer:
Name: www.byteguide.com
Address: 66.37.153.76

If this works, then your network is working and it is also likely that no firewall is blocking DNS traffic.

Your DNS servers could be broken, the network to your DNS servers could be broken, or your computer could be configured for the wrong DNS servers.

The next step is to manually check the DNS server settings on your computer:

Checking DNS Server Settings under Microsoft Windows

  • Click the “Start” button.
  • Click “Control”
  • If you are not already in Category View, click “Switch”

  • Doubleclick “Network”
  • Doubleclick the network connection which connects your computer to the Internet
  • Click “Properties”
  • Doubleclick “Internet Protocol (TCP/IP)”
  • Compare the values set for “Obtain DNS server address automatically”, “Preferred DNS server” and “Alternate DNS server” with the correct values for your network
  • Click OK
  • Click OK

Checking DNS Server Settings under Unix

Under Unix, you configure you DNS servers by editing the file /etc/resolve.conf:

# cat /etc/resolv.conf
domain byteguide.com
nameserver 208.25.104.7
nameserver 205.161.148.7

If the DNS settings on your computer are set correctly, your DNS servers could be broken. Contact your DNS administrator for support.