[nsd-users] wildcard interfaces and UDP

Vlad Glagolev stealth at sourcemage.org
Sat Feb 19 16:26:42 CET 2011


On Fri Feb 11 13:23:56 CET 2011 W.C.A. Wijngaards wrote:
> 
> Hi Vlad,
> 
> On 01/27/2011 01:08 PM, Vlad Glagolev wrote:
> > Hello there,
> > 
> > our NSD setup is pretty simple, however the server one isn't.
> > 
> > there are 2 servers sharing one IP-address inbetween via CARP.
> > though, a problem:
> 
> This messes with the routes and interfaces, right?  NSD may need to have
> ip-address: specified by hand, with the full IP addresses it services
> (to avoid it calling the OS with zero IP and letting the route tables do
> the wrong things).

oh I see, but well.. when you run apache, snmpd or anything else, it handles
such situation pretty carefully, no?

the idea is one more ip address is added dynamically as an alias to physical
interface:

ifconfig eth0:0 xx.xx.xx.xx netmsk yy.yy.yy.yy

then I can connect to http, snmp, etc.

when i use wildcard interface for nsd, static IP address works fine, but not
that "dynamic" one.

> 
> > if "ip-address:" is specified, everything works flawlessly, otherwise
> > dig returns timeout error. But tcp-connection works fine, and "dig -t
> > A @... ... +tcp" returns correct answer.
> 
> If everything works fine, then, it is fine?

the problem is: I can't specify it on both machines, since it can belong to
the only one. it's handled dynamically by CARP. and when I put non-existent
IP-address, NSD failes to start while binding to non-existent IP.

> 
> > tried to turn off firewall, disable ipv6, also some different
> > configurations: no changes.
> > 
> > Linux 2.6.35, NSD 3.1.1-3.2.7. Is it a bug or a feature?
> 
> I do not understand what the bug or feature you are talking about is.

the topic ;-)

> 
> Best regards,
>    Wouter

-- 
Dont wait to die to find paradise...
--
Cheerz,
Vlad "Stealth" Glagolev
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