[Dnsmasq-discuss] Mac Darwin confusion

Geert Stappers stappers at stappers.nl
Tue Aug 4 12:01:59 BST 2020


On Tue, Aug 04, 2020 at 08:18:24AM +0700, Bernd Prager wrote:
> On 8/4/20 3:36 AM, Andrew Miskell wrote:
> > On Aug 3, 2020, at 3:06 PM, Geert Stappers <stappers at stappers.nl> wrote:
> > > On Mon, Aug 03, 2020 at 07:04:47PM +0200, No Yes No Questions wrote:
> > > > On Mon, Aug 03, 2020 at 10:44:07PM +0700, Bernd Prager wrote:
> > > > > Hi all,
> > > > > 
> > > > > I got something I can't wrap my head around. I have a QNAP NAS that I
> > > > > thought would be nice for hosting a DNSMASQ service for DNS and DHCP. Setup
> > > > > went smooth and all my Linux clients behave wonderfully, except my Mac
> > > > > client:
> > > > > 
> > > > > Querying a host from Linux goes perfect:
> > > > > 
> > > > > -=[22:29:35][bernd at hoenir ~]=- dig @qnap freyja
> > > > > 
> > > > > ;; QUESTION SECTION:
> > > > > ;freyja.                                IN      A
> > > > > 
> > > > > ;; ANSWER SECTION:
> > > > > freyja.                 0       IN      A 192.168.1.7
> > > > > 
> > > > > ;; Query time: 0 msec
> > > > > ;; SERVER: 192.168.1.5#53(192.168.1.5)
> > > > .5
> > > > 
> > > > 
> > > > > -=[22:29:37][bernd at hoenir ~]=-
> > > > >   ping -c 1 freyja
> > > > > PING freyja.prager.homeip.net (192.168.1.7) 56(84) bytes of data.
> > > > > 64 bytes from freyja.prager.homeip.net (192.168.1.7): icmp_seq=1 ttl=64
> > > > > time=131 ms
> > > > > 
> > > > > --- freyja.prager.homeip.net ping statistics ---
> > > > > 1 packets transmitted, 1 received, 0% packet loss, time 0ms
> > > > > rtt min/avg/max/mdev = 131.374/131.374/131.374/0.000 ms
> > > > > 
> > > > > Now the same query from my Mac sees the host but still can't connect to it:
> > > > > 
> > > > > [bernd at loki ~$ dig @qnap freyja
> > > > > 
> > > > > ;; QUESTION SECTION:
> > > > > ;freyja.                IN    A
> > > > > 
> > > > > ;; ANSWER SECTION:
> > > > > freyja.            0    IN    A    192.168.1.7
> > > > > 
> > > > > ;; Query time: 7 msec
> > > > > ;; SERVER: 192.168.1.5#53(192.168.1.5)
> > > > The same .5
> > > > 
> > > > > [bernd at loki ~$ ping -c 1 freyja
> > > > > ping: cannot resolve freyja: Unknown host
> > > > > 
> > > > > Does anybody have an idea what I am missing?
> > > > Yes
> > > > 
> > > DNS query tool `dig` at the Linux system does add domain name to the request.
> > > 
> > > `dig` at the MacOS system doesn't add a domain name, which is correct behaviour.
> > > 
> > > 
> > > For `ping` is it OK to add a domainname. It seems the Mac is not aware
> > > of domain name.
> > > 
> > > Find a way to tell the Mac about the .prager.homeip.net domain name.
> > > 
> > macOS will know about the domain if it’s told by the DNS server via DHCP.
> > 
> > However, macOS will cache information and sometimes will need a
> > forced reset to pick things up. Using "dscacheutil -flushcache;sudo
> > killall -HUP mDNSResponder” should reset the DNS cache on macOS.
> > 
> > 
> 
> 
> Thank you all for your kind help. I wanted to give the list a quick update:
> 
> While I have not resolved the issue yet, despite trying all the suggestions
> above (except Geert's ".5" comment which I need to do some research on what
> that actually means),

> > > > > ;; SERVER: 192.168.1.5#53(192.168.1.5)
> > > > .5

> > > > > ;; SERVER: 192.168.1.5#53(192.168.1.5)
> > > > The same .5

The last octet of the IPv4 address.


> I have nailed the likely culprit to the NordVPN I have
> running with my particular user. Pinging my other Intranet-Hosts from any
> other user on my Mac without the VPN running actually works. It seems that
> the VPN does something to my network configuration that its not telling me.
> The Mac DNS utility still claims to point to my DNSMASQ instance.
> 
> By the way, pinging my internal host with a full domain name
> freyja.prager.homeip.net resolves to my DynDNS external network IP address.


Nice, please explore it further, you learn a lot from it.



Groeten
Geert Stappers
-- 
Silence is hard to parse



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