[uml-devel] No DNS resolution on uml guest

[uml-devel] No DNS resolution on uml guest

[Roland Kaeser]

Hello All

I have a very strange behaviour on a uml guest system. 
The guest os (Fedora 2) cannot make any name resolution but the "normal" network
works properly.
I'm using the guest file system which i have snapshoted from a special installation
on a "real" machine. The guest file system and the machine installation have exactly
the same files. When I try to make the dns resolution on the original machine it
works well.  The resolution on the uml guest doesn't works event when the whole
package filter (iptables) is disabled and set to accept.
I use a linux bridge to communicate with the outside world.

Roland


	

	
		
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Re: [uml-devel] No DNS resolution on uml guest

[roland]

Hi Roland,
> The guest os (Fedora 2) cannot make any name resolution but the "normal" network
> works properly.
and you can ping the nameserver from inside the uml ?
do you see any udp-packets leaving the uml (do a tcpdump on the uml`s eth0 and on the hosts bridge interface) ?
if not, can you try to send some udp packets from/to the uml with "nc" (netcat - network admins swiss army knife) to make sure, that
it probably isn`t a problem with the resolver ?

> The guest file system and the machine installation have exactly
> the same files. When I try to make the dns resolution on the original machine it
> works well.  The resolution on the uml guest doesn't works event when the whole
> package filter (iptables) is disabled and set to accept.
You use different IPs for them , do you ?
If not, and if you use the machines one after each other, keep in mind that the ARP-Cache of the DNS-Server (if on the same lan) or
the first Hop(Router) between your UML and the DNS Server need to expire the MAC/IP pair it has learned before, until it can
communicate with the same IP "on another MAC" again.

Roland(/too)


----- Original Message ----- 
From: "Roland Kaeser" <roli8200@yahoo.de>
To: <user-mode-linux-devel@lists.sourceforge.net>
Sent: Tuesday, December 07, 2004 5:37 PM
Subject: [uml-devel] No DNS resolution on uml guest


> Hello All
>
> I have a very strange behaviour on a uml guest system.
> The guest os (Fedora 2) cannot make any name resolution but the "normal" network
> works properly.
> I'm using the guest file system which i have snapshoted from a special installation
> on a "real" machine. The guest file system and the machine installation have exactly
> the same files. When I try to make the dns resolution on the original machine it
> works well.  The resolution on the uml guest doesn't works event when the whole
> package filter (iptables) is disabled and set to accept.
> I use a linux bridge to communicate with the outside world.
>
> Roland
>
>
>
>
>
>
> ___________________________________________________________
> Gesendet von Yahoo! Mail - Jetzt mit 250MB Speicher kostenlos - Hier anmelden: http://mail.yahoo.de
>
>
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now.
> http://productguide.itmanagersjournal.com/
> _______________________________________________
> User-mode-linux-devel mailing list
> User-mode-linux-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
>



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Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
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