strange network problem of 4 pcs within a router

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unit85
Posts: 15
Joined: 2006/02/10 08:24:18

strange network problem of 4 pcs within a router

Post by unit85 » 2008/02/22 03:15:05

Within a router, I have 4PCs, 1 with windows and 3 with centos 4. It's possible to login from one to another for 3 centos machines and it's also possible to login centos machines from windows machine. Only windows machine and one centos machine can access outside of router and be accessed rom PC outside of the router. Anybody the possible problem for other two PC with centos? Thank you very much. By the way, these 4 PCs worked okay until I rebooted 2 PCs once.

gerald_clark
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Location: Northern Illinois, USA

Re: strange network problem of 4 pcs within a router

Post by gerald_clark » 2008/02/22 14:49:34

Sounds like a DNS or router problem.
Examine the file /etc/resolv.conf on all 4 CentOS machines.
Also check the output of 'route -n'.

I think you will find the difference.

unit85
Posts: 15
Joined: 2006/02/10 08:24:18

Re: strange network problem of 4 pcs within a router

Post by unit85 » 2008/02/24 05:22:26

Thank you for your help. I examined the file /etc/resolv.conf and the output of 'route -n', but found no difference among these machines. It's really strange.


[quote]
gerald_clark wrote:
Sounds like a DNS or router problem.
Examine the file /etc/resolv.conf on all 4 CentOS machines.
Also check the output of 'route -n'.

I think you will find the difference.[/quote]

yyagol
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Location: 32 4′N 34 47′E
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Re: strange network problem of 4 pcs within a router

Post by yyagol » 2008/02/25 19:04:12

Are the PC's behind NAT ?

unit85
Posts: 15
Joined: 2006/02/10 08:24:18

Re: strange network problem of 4 pcs within a router

Post by unit85 » 2008/02/26 02:38:47

Yes, it's true. Since I am a newbie, I don't know what 'behind NAT' means and what kind of step I should take then. Please give me further advices, thank you.


[quote]
yyagol wrote:
Are the PC's behind NAT ?[/quote]

yyagol
Posts: 1015
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Re: strange network problem of 4 pcs within a router

Post by yyagol » 2008/02/26 20:35:43

OK ,
Network Address Translation. A method for translating internal IP addresses or network addresses into a single globally
unique IP address , usually a translation on a private IP into public IP .
http://en.wikipedia.org/wiki/Network_address_translation

Example :

if you surf to http://www.whatismyip.com/
and you see something like [color=0000FF]Your IP Address Is 84.110.213.167[/color]
and you're eth has different IP , one from this subnet http://en.wikipedia.org/wiki/Private_network
then yes you are behind NAT .

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