On Wed, Feb 21, 2018 at 07:02:45PM +0100, Geert Stappers wrote:
> On Wed, Feb 21, 2018 at 05:03:34PM +0000, Donald Muller wrote:
> > > > > On Wed, Jan 31, 2018 at 10:22:53AM +0100, Geert Stappers wrote:
> > > > > > On Tue, Jan 30, 2018 at 05:08:05PM +0000, Donald Muller wrote:
> > > > > > >
> > > > > > > Using Microsoft DNS server
> > > > > > > [~] # time nslookup www.microsoft.com 192.168.22.200 Address 1:
> > > > > > > 192.168.22.200 djmfs1.djmuller.com
> > > > > >
> > > > > > Programm nslookup did a reverse lookup on used DNS address and got
> > > > > > back a FQDN
> > > > > >
> > > > > > > Using dnsmasq
> > > > > > > [~] # time nslookup www.microsoft.com 192.168.22.220 Address 1:
> > > > > > > 192.168.22.220 DJMFS2
> > > > > >
> > > > > > Non Fully Qualified Domain Name for the used DNS address

So we know that the reverse DNS data source is some what sloppy configured.

||| 192.168.22.200 djmfs1.djmuller.com
||| 192.168.22.220 DJMFS2

But the real thing I'm trying to tell:  extra (unwanted??) reverse lookup happen


> > > > > > Wow, a full forty seconds ...
> > > > > >
> > > 
> > > I'm not convinced that the culprit is in  dnsmasq.
> > > Please continue to find proof  ...

Because you have a interesting probleem ...


> > > > > > > What additional information do you need?
> > > > All devices, including the router, are connected at 1GB to a switch.
> > > 
> > > The testclient what does it have in /etc/resolv.conf while testing?
> > > Other tools for `nslookup`, such as `dig` and `host`, what timing results 
> > > have
> > > those?
> > > The QNAP NAS with dnsmasq, how much traffic must it handle?
> > 
> > The test client has the following in reslov.conf
> > 
> > [~] # cat /etc/resolv.conf
> > nameserver 192.168.22.220
> > nameserver 192.168.22.242
> > 
> > host shows the following:
> > 
> > [~] # time host www.microsoft.com 192.168.22.220
> > Using domain server:
> > Name: 192.168.22.220
> > Address: 192.168.22.220#53
> > Aliases:
> > 
> > www.microsoft.com is an alias for www.microsoft.com-c-3.edgekey.net.
> > www.microsoft.com-c-3.edgekey.net is an alias for 
> > www.microsoft.com-c-3.edgekey.net.globalredir.akadns.net.
> > www.microsoft.com-c-3.edgekey.net.globalredir.akadns.net is an alias for 
> > e13678.dspb.akamaiedge.net.
> > e13678.dspb.akamaiedge.net has address 104.88.47.193
> > e13678.dspb.akamaiedge.net has IPv6 address 2001:418:143c:19e::356e
> > e13678.dspb.akamaiedge.net has IPv6 address 2001:418:143c:1a9::356e
> > 
> > real    0m0.050s
> > user    0m0.001s
> > sys     0m0.001s

That is much better than forty seconds ...

> > dig is not installed.

Install it. Rule out that we are dealing with a bogus nslookup.

> > 
> > The QNAP NAS is not handling much traffic. If is a home file server with 
> > minimal traffic.
> > 
> > I also set up dnsmasq on a second NAS with just DNS running, no DHCP. This 
> > NAS is used for backups so normally has no traffic. I get the same long 
> > times
> > 
> > [~] # time nslookup www.microsoft.com 192.168.22.242
> > Server:    192.168.22.242
> > Address 1: 192.168.22.242 djmfs3.djmuller.com

A reverse DNS lookup was performed
> > 
> > Name:      www.microsoft.com
> > Address 1: 104.88.47.193 a104-88-47-193.deploy.static.akamaitechnologies.com

A reverse DNS lookup was performed

> > Address 2: 2001:418:143c:19e::356e
> > Address 3: 2001:418:143c:1a9::356e
> > 
> > real    0m40.071s
> > user    0m0.000s
> > sys     0m0.001s
> > 
> > What times do you get if you do a nslookup on www.microsoft.com?
> 
> | $ time nslookup www.microsoft.com 172.24.0.7
> | Server:             172.24.0.7
> | Address:    172.24.0.7#53

No sign that nslookup did a reverse lookup.

> | Non-authoritative answer:
> | www.microsoft.com   canonical name = www.microsoft.com-c-3.edgekey.net.
> | www.microsoft.com-c-3.edgekey.net   canonical name = 
> www.microsoft.com-c-3.edgekey.net.globalredir.akadns.net.
> | www.microsoft.com-c-3.edgekey.net.globalredir.akadns.net    canonical name 
> = e13678.dspb.akamaiedge.net.
> | Name:       e13678.dspb.akamaiedge.net
> | Address: 104.73.152.80

No sign that nslookup did a reverse lookup.

> | real        0m0,261s
> | user        0m0,006s
> | sys 0m0,006s

Considered "fast"

> | $ time host www.microsoft.com 172.24.0.7
> | Using domain server:
> | Name: 172.24.0.7
> | Address: 172.24.0.7#53
> | Aliases: 
> | 
> | www.microsoft.com is an alias for www.microsoft.com-c-3.edgekey.net.
> | www.microsoft.com-c-3.edgekey.net is an alias for 
> www.microsoft.com-c-3.edgekey.net.globalredir.akadns.net.
> | www.microsoft.com-c-3.edgekey.net.globalredir.akadns.net is an alias for 
> e13678.dspb.akamaiedge.net.
> | e13678.dspb.akamaiedge.net has address 104.73.152.80
> | e13678.dspb.akamaiedge.net has IPv6 address 2a02:26f0:f4:196::356e
> | e13678.dspb.akamaiedge.net has IPv6 address 2a02:26f0:f4:19f::356e
> | 
> | real        0m0,096s
> | user        0m0,008s
> | sys 0m0,004s

faster as nslookup.


Groeten
Geert Stappers
-- 
Leven en laten leven

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