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Linux networking problem - cannot see internet

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mwhager

IS-IT--Management
Jun 8, 2000
27
US
I have a redhat linux 6.2 box that is sitting on our lan. IP addresses on our LAN are 192.0.0.x. We run NT 4.0 with MS proxy installed and our users access the internet via proxy. I am trying to get the redhat linux box to see the internet. I can ping internal addresses no problem. I cannot ping external addresses by name or by ip address. This is what I have set up so far -
Configured /etc/resolv.conf as follows:
domain xxxxxxxx.com
nameserver 1 external address of our ISP nameserver.
nameserver 2 2nd external address of our ISP nameserver.
i tried using the IP address of the router our ISP gave us as a gateway address. I also tried using the internal address of our proxy server (altho I couldn't imagine that working - and it didn't!).

i am really stumped here and would appreciate some guidance.

Thanks.
 
have u tried doing a trace route to see where it got killed?
 
Are you running NAT ? If so you need to use the internal network address of the device where NAT is installed as yuor gateway.

IE: NAT has an internal and external address.

However if your running NAT this make not solve your problem.

Why are you using MS PROXY, I have heard nothing positive about it ?



-Danny






 
first identify through which internal router you are going outside even to isp gateway.
check are you able to ping internal router.
if you are using proxy server to go outside then, are your internal addresses are on private address i.e 10.x.x.x, 192.168.x.x, 172.16.x.x.

if you are able to ping internal router check your default gateway on your linux machine.
check and tell what you have ?
hope will help something.
 
My proxy server has two NICs - one with an internal address of 192.0.0.x and one with external address. I am not running NAT. My internet router sits behind the proxy. It only has an external address.

I have had good experiences with MS Proxy in the past and it meets my needs pretty well.

Thanks for your assistance.

I will try a trace route too.
 
Here is what I can add, maybe it will help. I have a 6.2 setup and here is the settings I used. In /etc/resolv.conf I have the lines:

search yourdomain.com
nameserver xxx.xxx.xxx.123

In my /etc/sysconfig/network-scripts/ifcfg-eth0 I put the other info. Such as my ip (make sure it is allowed to surf according to your proxy server), (broadcast, network, and netmask) address's which should be ok under normal conditions, and your gateway address (in your case you should try to use the inside address of your proxy server). After you make these changes use the ifdown and ifup scripts to reset your card. You can just reboot if you want to also.

If it still fails you will need to check your broadcast, network, and netmask address's. This should not affect you unless your linux box is right next to the router from the ISP with say only 8 ip's or something.

Good luck,

Troy
 
hi there!

well, think that the DG is wrong.
use your MS-proxy (internal adress) as DG for your LinuxBox.
then try to ping it. (like everybody else is telling you :) )

then the final test to be shure that the nameresolution is working correctly is to do a "nslookup"
try that.
if you get a message like "Cant resolv adress to ...yourDNS.. blabla"
then there is no contact between LAN->ISP.
GOOD LUCK!
//DG
 
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