Internet troubleshooting : Java Glossary
- Internet Troubleshooting
What do you do when your connection to the Internet stops working, or when you
cannot reach a particular site. Perform the following steps in order until it
Do a Google
search for wombats
to see if it was just one site down, or if
your entire Internet connection has failed. Google itself is almost never down. If
just one site is failing go to Just One Site Is Down other
wise carry on with If your Internet Connection in General
If your Internet Connection in General has Failed
- Look at the lights on your router. They should be flashing. If they are not
wiggle the corresponding connection until they start flashing.
- Wiggle the Ethernet connection at the back of your computer and any other place
a vaguely Internet-related cable fits into a socket.
- Turn your router off then on again.
- Turn your cable modem/ADSL modem off then on again.
- At the command line type:
ipconfig /renewThis will renew you IP and connection to some DNS (Domain Name Service) servers.
- Login to your modem and ask it to renew its DHCP (Dynamic Host Configuration Protocol) connection to the
- Call your IAP (Internet Access Provider)
and ask them if they are having trouble with cable/ADSL service to your address.
- Your router probably has a command to ask it to renew its
connection. Tell it to do that. You can also try turning your router off and back
on again to reset it.
Just One Site Is Down
If you can see sites generally but theory is one site you cannot reach, follow this
- Find out if the site is down just for you or for everyone. If no one
can see the site, all you can is wait for them to get themselves back on the air.
- If it is only you having problems reaching the site, the problem may be your
DNS (Domain Name Service) cache is pointing to the wrong IP. At the command line
ipconfig /flushdnscacheto clear your cache.
- Your router probably has a command to ask it to renew its DHCP (Dynamic
Host Configuration Protocol) connection. Tell it to do that. You can also try
turning your router off and back on again to reset it.
- You can renew your computer’s DHCP connection by, at the
command line, by typing:
- You can find out some technical details about your Internet connection,
including the IPs of your current DNS servers, with:
- You might like to keep track of the IPs of your crucial sites. Then, in a
pinch, if DNS
is not working at all, you can insert those IPs into your hosts. file and at least access those sites. You can find out a
site’s IP with ping. The problem with
putting them in permanently is the IPs change from time to time and stop working.
The advantage of putting commonly used domains in your hosts. file is the lookup is instantaneous.
Alternate DNS Servers
Your DNS servers may have the wrong IP or may not have the domain you want on file. If your ISP is not providing reliable DNS servers, or you suspect there is a
problem with them you can try out some alternates. Of course, these alternates may fail too, so don’t forget how to put them back the way they were. Since your ISPs servers are physically
close, they should provide the fastest service. To configure DNS servers, Click Control Panel ⇒ Network & Internet ⇒ Network Connections ⇒ right click Properties.
- Google DNS Servers: 18.104.22.168 and 22.214.171.124
- IsItDown DNS servers: 126.96.36.199 and 188.8.131.52
- It might be wise to write down your current
ISP-supplied DNS servers so you can manually force their use if DHCP stops working.
- You might want to mix servers from two different sources so it will continue to work even if one source goes down.