I have been facing this problem for about a week. Try to troubleshoot using google but to no avail. I have to NIC cards in my server. I was using the first one and this problem came up. I changed to the other one. It work for about a week and the same problem came up. I cannot ping or browse internet from this machine, however, i can ping, ssh and connect to this machine from another one.

Any help will be appreciated

Hi,

A little more information would be helpful. What distribution?

Why & how did the first NIC quit?

What type NIC and is it embedded or card? What about the link media (cable bad)?

You say you can ping from outside, what about errors listed from the output of 'ifconfig -a' from both machines.

What does the logs show for any relative errors on the machine in question?

What about the LAN? Does your router/switch/hub function properly?

Hi onebuck, thanks for the tips. My distro is CentOS 5.3. I am using this box as a webserver. My NIC is embedded and there is no problem with the physical connection as i can connect to this machine remotely. I can access the other machines using their ip address from this machine but not with their domain name. When i do the follwing in this machine this is the results:

First:
# /etc/rc.d/init.d/network restart
Shutting down interface eth1: [ OK ]
Shutting down loopback interface: [ OK ]
Bringing up loopback interface: [ OK ]
Bringing up interface eth1: RTNETLINK answers: File exists
Error adding address (ip) for eth1.
[ OK ]
Second:
$ ping www.google.com
ping: unknown host www.google.com


Third:
#vi /etc/resolv.conf

# Generated by NetworkManager
# No nameservers found; try putting DNS servers into your
# ifcfg files in /etc/sysconfig/network-scripts like so:
#
# DNS1=xxx.xxx.xxx.xxx
# DNS2=xxx.xxx.xxx.xxx
# DOMAIN=lab.foo.com bar.foo.com

In the third case when i put the nameservers manually and restart the network the same results comes.

Any help will be appreciated. Thanks

Sounds like something has gone duff with your resolv.conf if you cannot do name resolution but you can ping stuff. Either that or a routing issue.

Do you have a static IP address set on the cards, or do you use DHCP?

Hi,

It does sound like you have a 'DNS' problem. You can try a third level 'DNS' like Verizon's;

But you should use your ISP 'DNS'.

Yeah i have static public ip address used in the server. we have our own primary and secondary name servers i have been using that for all our dns purposes. what is the use of verizon? when i manually put our dns ips in the /etc/resolv.conf and restart the network the result is the same. i.e the resolv.conf becomes empty again without any name server's details. Thanks for your help.

Hi,

The verizon is third level DNS. It can be by anyone.

i have same issue
Bringing up interface eth1: RTNETLINK answers: File exists
Error adding address (ip) for eth1.

This is my resolution.

After u do #setup
u set name server then saved.
And do #service network restart

Now do #vi /etc/resolv.conf
U will never see any name server here.

Some reasons i dont know why??????

So when u do #setup
u set name server then saved.

DONT NEED TO DO THIS #service network restart

#ping yahoo.com

It works wellllllllllll


Enjoy.......................