[CentOS] NetworkManager frustration...

Timothy Madden terminatorul at gmail.com
Fri May 11 11:02:21 UTC 2012


On 05/11/2012 01:38 PM, Nux! wrote:
> On 11.05.2012 11:16, Timothy Madden wrote:
>> On 05/11/2012 11:14 AM, Nux! wrote:
>>> On 10.05.2012 11:55, Timothy Madden wrote:
>>>> I would like to use dnsmasq to cache nameserver query results, and
>>>> I
>>>> have set dhcp to prepend the 127.0.0.1 name-server to the list of
>>>> nameservers. dnsmasq would then automatically exclude the localhost
>>>> as a
>>>> name server and use all the others from the list provided by dhcp.
>>>>
>>>> But it was too nice to be true, because NetworkManager was there,
>>>> ready
>>>> to mess up anything I try to do, including the list of name servers
>>>> that
>>>> dhclient puts in /etc/resolv.conf.
>>>>
>>>> Is there really no way to convince that idiotic piece of software
>>>> that
>>>> it suffered too much brain damage in order for it to manage even a
>>>> simple eth0 interface, and that dhclient can properly take care of
>>>> the
>>>> resolver configuration by itself ?
>>>>
>>>> Or do I have to turn it off entirely ?
>>>>
>>>> Is there a better way to have dhclient write the list of DNS
>>>> servers,
>>>> that dnsmasq could then use ?
>>>>
>>>> Thank you,
>>>> Timothy Madden
>>>>
>>>> _______________________________________________
>>>> CentOS mailing list
>>>> CentOS at centos.org
>>>> http://lists.centos.org/mailman/listinfo/centos
>>>
>>> I'm doind the same thing (running local cache) and NM works just
>>> fine.
>>> You should be setting NM to use the "DHCP (addresses only)" as in
>>> this
>>> image: http://img.nux.ro/4PsJ-dhcpnmlocaldns.png
>>> Put the upstream resolvers in some other file, e.g. /etc/nameservers
>>> and tell dnsmasq to get it's nameservers from there.
>>> Or just run a full fledge nameserver yourself and get rid of dnsmasq
>>> (I
>>> use pdns-recursor).
>>
>> But if I make a separate file like /etc/nameservers than I will have
>> to
>> update it every time DHCP returns a different list of nameservers.
>>
>> I tried to write a dhclient-exit-hooks script in /etc/dhcp that would
>> generate that file, but guess what ? Network Manager supresses the
>> normal dhclient script file ! (probably uses its own) I tried to add
>> it
>> back with
>>            DHCLIENTARGS="-sf /sbin/dhclient-script"
>> with no effect, because NetworkManager takes care that such an
>> approach
>> would not work !
>>
>> And if I try to read some documentation about how NetworkManager
>> would
>> achieve the same effect, there is nothing clear in its manual pages,
>> you
>> can only find some (vague) settings about NM plugins.
>>
>> How can such software be part of CentOS _base_ distribution ?
>
> Well.. in many cases NM works well, hence it's presence in @base. Now I
> don't know how to solve your problem nor do I have time to investigate;
> all I can recommend is run a local dns cache (pdns-recursor, bind,
> tinydns etc).

Whatever my namer server is (bind or dnsmasq) I still want to read the 
nameservers listed by DHCP, to pass them to it, and I still NM to allow 
DHCP to list its nameservers, but to only write 127.0.0.1 in 
/etc/resolv.conf.

So the way I see it, the problem is not dnsmasq, it is the lack of 
options in NM.

Thank you for your support,
Timothy Madden




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