On Tue, 2005-11-15 at 17:00 +0300, Dmitry Koterov wrote:
> Hello.
> 
> Shortly:  when  I use BIND (or PowerDNS) inside vserver listening
> ALL addresses (0.0.0.0), nslookup to server 127.0.0.1 shows error
> message   "reply   from   unexpected  source:  213.248.62.106#53,
> expected 127.0.0.1#53"
Which is true, as your nameserver (powerdns or bind) is assigned
your vserver interface as primary interface and answers are sent with
that source.

> Long  description.  I have installed linux-vserver (named "zulu")
> on  kernel  2.6.12.5  and  set  up  one  real  IP  for  it      -
> 213.248.62.106:
> 
> [EMAIL PROTECTED] /]# ifconfig
> eth0      Link encap:Ethernet  HWaddr 00:30:48:75:13:D2
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:39623139 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:18575687 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:50148146621 (46.7 GiB)  TX bytes:1249870165 (1.1 GiB)
>           Base address:0x3000 Memory:dd300000-dd320000
> 
> eth0:zulu Link encap:Ethernet  HWaddr 00:30:48:75:13:D2
>           inet addr:213.248.62.106  Bcast:213.248.62.255  Mask:255.255.255.0
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           Base address:0x3000 Memory:dd300000-dd320000
> 
> First question: why doesn't ifconfig show "lo" interface?
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lo is not assigned to your context and therefor not shown.

> Then,    I    installed    named   (BIND),   compiled   it   with
> --disable-linux-caps  before.  BIND  listens  on all IP addresses
> inside vserver:
> 
> [EMAIL PROTECTED] /]# netstat -na
> Active Internet connections (servers and established)
> Proto Recv-Q Send-Q Local Address               Foreign Address             
> State
> tcp        0      0 213.248.62.106:53           0.0.0.0:*                   
> LISTEN
> udp        0      0 213.248.62.106:53           0.0.0.0:*
> ...
This shows only listening on your vserver ip address. And answering to
the world ;)

> Then I try nslookup:
> 
> [EMAIL PROTECTED] /]# nslookup
> > server 127.0.0.1
> Default server: 127.0.0.1
> Address: 127.0.0.1#53
> > hostmag.ru.
> ;; reply from unexpected source: 213.248.62.106#53, expected 127.0.0.1#53
> ;; reply from unexpected source: 213.248.62.106#53, expected 127.0.0.1#53
FWIR: The first interface brought up in the context is 'assigned' the
functionality of lo0.

For a more detailed explaination you have to rely on the
developers/experts answer(s)... I'm just a simple end user ;)


> Second  question: what's  wrong?  Why  BIND tries to answer from
> vserver IP address, but NOT from localhost which I used?
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
localhost is just a name, so I guess you're refering to the loopback
ip address which defaults to 127.0.0.1

As I explained above, 127.0.0.1 is not assigned to your guest context
and so is not used as reply address by your nameserver

> I  have  also  tried  PowerDNS  instead of BIND - absolutely same
> effect.
As to be expected.

> I  do not want to write 213.248.62.106 in my resolv.conf, because
> this  IP may be changed one fine day, or vserver will be moved to
> another machine.
It always needs an ip address, so why not rewrite /etc/resolv.conf
from pre-start or post-start and use the ip address assigned at time
as nameserver.

> Seems networking stack isolation in linux-vserver is not finished
> yet?
I don't know the answer to this one, but it seems that it is doing
its job quite nicely ;)

-- 
Regards,
Dennis Roos

Network Engineer @ InTouch N.V.
Middenweg 76
1097 BS Amsterdam
Tel: +31 (0)20 6752060
Fax: +31 (0)20 6758429

-=[Assumption is the mother of all f*ckups]=-


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