google.comというサーバーが見つかりません/google.com can not be found.

addittioal info

when I use gnome-terminal,
the return massage of
ping www.google.com
is
ping: unknown host www.google.com

Hi Yotan,

Just to check if the problem lies with your dns or with something else, try the following commands:

nslookup google.com

Then also try pinging one of googles ip addresses (209.85.171.100|72.14.205.100|74.125.45.100).

Post the results you get.

Henry

Hi Henry,
I deeply appreciate your answering my question.

"192.168.11.1" is the Broad Band Router address(Buffolo BBR 4HG).

I typed nslookup google.com

result is as follows:

Server: 192.168.11.1
Address: 192.168.11.1#53

Non-authoritative answer:
Name: google.com
Address: 74.125.45.100
Name: google.com
Address: 209.85.171.100
Name: google.com
Address: 72.14.205.100

I tried ping giving the address you showed as argument like this:
~$ ping 209.85.171.100

result is as follows:

PING 209.85.171.100 (209.85.171.100) 56(84) bytes of data.
64 bytes from 209.85.171.100: icmp_seq=1 ttl=237 time=157 ms
64 bytes from 209.85.171.100: icmp_seq=2 ttl=237 time=145 ms
64 bytes from 209.85.171.100: icmp_seq=3 ttl=237 time=145 ms
64 bytes from 209.85.171.100: icmp_seq=4 ttl=237 time=157 ms
64 bytes from 209.85.171.100: icmp_seq=5 ttl=237 time=157 ms
64 bytes from 209.85.171.100: icmp_seq=6 ttl=237 time=147 ms
^C
--- 209.85.171.100 ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 5019ms
rtt min/avg/max/mdev = 145.007/151.771/157.550/5.793 ms

and 72.14.205.100
~$ ping 72.14.205.100

result is as follows:

PING 72.14.205.100 (72.14.205.100) 56(84) bytes of data.
64 bytes from 72.14.205.100: icmp_seq=1 ttl=237 time=224 ms
64 bytes from 72.14.205.100: icmp_seq=2 ttl=237 time=214 ms
64 bytes from 72.14.205.100: icmp_seq=3 ttl=237 time=225 ms
64 bytes from 72.14.205.100: icmp_seq=4 ttl=237 time=226 ms
64 bytes from 72.14.205.100: icmp_seq=5 ttl=237 time=227 ms
^C
--- 72.14.205.100 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4015ms
rtt min/avg/max/mdev = 214.893/223.880/227.944/4.673 ms

and then 74.125.45.100

~$ ping 74.125.45.100

result is as follows:

PING 74.125.45.100 (74.125.45.100) 56(84) bytes of data.
64 bytes from 74.125.45.100: icmp_seq=1 ttl=239 time=199 ms
64 bytes from 74.125.45.100: icmp_seq=2 ttl=239 time=203 ms
64 bytes from 74.125.45.100: icmp_seq=3 ttl=239 time=202 ms
64 bytes from 74.125.45.100: icmp_seq=4 ttl=239 time=205 ms
64 bytes from 74.125.45.100: icmp_seq=5 ttl=239 time=214 ms
^C
--- 74.125.45.100 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4016ms
rtt min/avg/max/mdev = 199.540/204.916/214.091/4.928 ms

Ok, that seems to be working correctly.
The next two things I would check is make sure that your mtu isn't set too high, and that if you have any proxy settings, make sure they are correct.

Then if that fails, I am a bit stuck for ideas sorry.

I deeply appreciate your help.

about proxy setting

There is no proxy setting. A Broad Band Router(DNS server at the same time because it gives the computers ipaddresses like 192.168.11.2) is connected to the Modem. This computer is directly connected through Ethernet cable to the Broad Band Router.

about mtu

Please tell me how to check the mtu .

That makes life easier that you are not using a proxy.

Something I have over looked, can you access any google pages? Do you get the same result trying to get to http://www.google.co.jp, http://www.google.co.nz, and http://www.google.com?

For mtu info:

Wikipedia:
http://en.wikipedia.org/wiki/Maximum_transmission_unit

and a couple of forum threads you should read:

http://ubuntuforums.org/showthread.php?t=226863

I appreciate your help.

about MTU:
I visited some web sites including the wikipedia.
I do not think I understood everything correctly about MTU.

I did not customize MTU. MTU must be default setting. I think MTU is automatically set.

Anyway,I typed,
ifconfig eth0 MTU 1500

and tried to browse www.google.com , but the page can not be accessed.

about other Google pages:
www.google.co.jp :server can not be found
www.google.co.nz :server can not be found
www.google.com :server can not be found
I get the same result.

Have you had any luck?

It's a long shot but you could try using another dns: http://www.opendns.com/