Local advertised IPv6 DNS cache server

RouterOS General
1

Hello.
I have Mikrotik cache DNS server at fc00::1 and it works. But I want to advertise it to clients (Windows, Android, Linux)
I read several topics:
http://forum.mikrotik.com/t/ipv6-advertise-router-as-dns/118071/1
http://forum.mikrotik.com/t/ipv6-advertise-router-as-dns/118071/1
http://forum.mikrotik.com/t/cant-get-dnsv6-from-slaac/118864/1
But still no luck.

Mikrotik is just saying me “handling only prefix delegation discarding”. I know that it cannot delegate IP’s, but it doesn’t even answer with DHCP options

My config:

[admin@MikroTik] > /ipv6 address print detail 
Flags: X - disabled, I - invalid, D - dynamic, G - global, L - link-local 
 0  G address=2a02:2698:2822:89dd:ce2d:e0ff:fe9b:862a/64 from-pool=ipv6-pool 
      interface=bridge actual-interface=bridge eui-64=yes advertise=yes 
      no-dad=no 

 1 DL address=fe80::ce2d:e0ff:fe9b:862a/64 from-pool="" interface=bridge 
      actual-interface=bridge eui-64=no advertise=no no-dad=no 

 2 DL address=fe80::9/64 from-pool="" interface=pppoe-out1 
      actual-interface=pppoe-out1 eui-64=no advertise=no no-dad=no 

 3 DL address=fe80::ce2d:e0ff:fe9b:8629/64 from-pool="" interface=ether1 
      actual-interface=ether1 eui-64=no advertise=no no-dad=no 

 4  G address=fc00::1/128 from-pool="" interface=bridge actual-interface=bridge 
      eui-64=no advertise=no no-dad=no 
[admin@MikroTik] > /ipv6 dhcp-client print detail 
Flags: D - dynamic, X - disabled, I - invalid 
 0    interface=pppoe-out1 status=bound duid="0x00030001cc2de09b8629" 
      dhcp-server-v6=fe80::a2f3:e4ff:fe04:fc01 request=prefix 
      add-default-route=yes default-route-distance=1 use-peer-dns=yes 
      pool-name="ipv6-pool" pool-prefix-length=64 prefix-hint=::/0 
      dhcp-options="" prefix=2a02:2698:2822:89dd::/64, 23h47m11s 
[admin@MikroTik] > /ipv6 dhcp-server print detail 
Flags: D - dynamic, X - disabled, I - invalid 
 0    name="server1" interface=bridge address-pool=static-only lease-time=30m 
      rapid-commit=yes use-radius=no preference=255 dhcp-option=dns,domain 
      route-distance=1 duid="0x00030001cc2de09b8629"
[admin@MikroTik] > /ipv6 dhcp-server option print detail 
 0 name="dns" code=23 value="0xfc000000000000000000000000000001" 
   raw-value="fc000000000000000000000000000001" 

 1 name="domain" code=24 value="'home.domain.org'" 
   raw-value="bignumber" 
[admin@MikroTik] > /ipv6 nd print detail 
Flags: X - disabled, I - invalid, * - default 
 0  * interface=all ra-interval=3m20s-10m ra-delay=3s mtu=unspecified 
      reachable-time=unspecified retransmit-interval=unspecified 
      ra-lifetime=30m hop-limit=unspecified advertise-mac-address=yes 
      advertise-dns=no managed-address-configuration=no other-configuration=yes 
[admin@MikroTik] > /ip dns print 
                      servers: 1.1.1.1,1.0.0.1,2606:4700:4700::1111,
                               2606:4700:4700::1001
              dynamic-servers: 
        allow-remote-requests: yes
          max-udp-packet-size: 4096
         query-server-timeout: 2s
          query-total-timeout: 10s
       max-concurrent-queries: 100
  max-concurrent-tcp-sessions: 20
                   cache-size: 2048KiB
                cache-max-ttl: 1w
                   cache-used: 164KiB
[admin@MikroTik] > /ipv6 pool print detail 
Flags: D - dynamic 
 0   name="ipv6-local-pool" prefix=fc00::/64 prefix-length=64 

 1 D name="ipv6-pool" prefix=2a02:2698:2822:89dd::/64 prefix-length=64 
     expires-after=23h46m11s
2

Someone described the behavior here:
http://forum.mikrotik.com/t/cant-get-dnsv6-from-slaac/118864/1
Seems like I am getting the same. Is there any solution?

3

Seems like turning off “Managed Address Configuration” helps for Windows, but Android and Linux still don’t get DNSv6 address.

4

Android does not support DHCPv6 unless you root the device and install third party software. Search Google for the details.

For me it works just fine with Linux, though you may have to make sure the firewall does not block the essential packets.

5

Thanks for answer, yes, you are right about Android, I forgot about that. But how to check it with Linux? I have Linux server, in /etc/resolv.conf there is only IPv4 192.168.88.1.

6

What does the network configuration look like?

7

I used default Mikrotik quick setup for home network (192.168.88.0/24). Default firewall setup and so on.

8

If it works for Windows, the problem probably isn’t on router.

I don’t use Linux as dynamic client, but what I saw in the past, it wasn’t as tightly integrated as Windows. Unless something changed, getting addresses from RA is handled by kernel itself, it just works by default. But to get additional info from DHCPv6, it needs properly configured client, which is separate program. I’d assume that by now this should be handled automatically by some network config scripts, but who knows. Check the manual for your distribution, if it perhaps needs some user interaction.

Of course the simplest solution (unless you’re building IPv6-only network) is to not bother. You don’t need resolvers with IPv6 addresses, it’s only transport, it doesn’t influence what queries can be answered. Resolvers with IPv4 addresses will do the same job.

9

Sorry for reviving this old post, but it describes also my problem.

On my windows and linux machines it works as expectd with DNS resolving. My mikrotik DNS is asked first and it can resolve local static domains, as well as all other hostnames on the net. And it caches my queries.

But on my mobiles (android…) it does not work as expected. Why?

I have a few set of devices running in my local network which I want to access via mobile. I setup static DNS entries for each device (out of a DHCP lease by script). And if I try to access these devices via mobile by their static dns name, it always fails.

I read that Android is in general and if available, trying to resolve via IPv6 DNS server. And if I check my IP settings on my mobile, I can see, that there are IPv6 based DNS servers. But first the two from my ISP, then the one from cloudflare (which I also added as main-dns in mikrotik setup), and that’s it… The mikrotik-router DNS which also has an IPv6 address is not found on my mobile. And even if it would, it must be the 1st, not the 2nd or 3rd…

There seems to be no option to tell the IPv6 configuration in RouterOS that it should only push the local DNS instead of the others to all IPv6 capable clients in my network.

I also read about setting up DHCPv6… But as far as I know, Android is not using DHCP without a rooted device :frowning:

Long story short: When using my android mobile, I’m not able to resolve local hosts via mikrotik builtin DNS…

Any ideas on how to solve this?

br,
Alex

10

@L11R

Did you solve the problem? I’m facing more and more issues with resolving hostnames with mikrotik DNS… which isn’t used on android mobiles, as the wrong name servers are advertised.
It’s not only Chrome which uses IPv6 nameservers instead of IPv4 nameserver (which has been advertised correctly), i face this now with different android apps too.

The only workaround is to force my clients to use static IPs and learn them by heart when trying to access them from android…



[1866]

11

Hmm, if I remove the “Advertise DNS” checkmark on /ipv6 nd for my bridge interface, my android devices only get ipv4 DNS servers. And that is my mikrotik router in first place.

With that, it works. But I fear this breaks other things. I will observer this further…