IPv6 and DNS

I setup a IPv6 tunnel from HE.net loosely following directions here:

http://wiki.mikrotik.com/wiki/Manual:My_First_IPv6_Network

Well it works somewhat. I have my IPv6 /64 bound to my wlan interface on routerboard and advertised. When my Win7 PC connects it gets an IPv6 address assigned automatically but no DNS server. When I manually assign the IPv6 DNS server from HE.net to the Win7 wifi interface then I can surf the Internet.

Is there anyway to automatically assign the DNS server as well???

Future versions of RouterOS will support DHCPv6. There is also draft work underway to use extensions to the stateless autoconfiguration mechanism to be able to pass DNS configuration.

RouterOS is already passing DNS server, however client must support this feature.

im no expert but isnt there a standard multicast address in ipv6 that you setup a dns resolver on and it gets used for that local subnet? will look into that.

Exactly what I thought. Windows assigns these by default it seems:

fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1

You cannot do an IPv6 DST NAT AFAIK to remap them to the outside IPv6 DNS server. So I just assigned the 3 IPv6’s to an ethernet port on the routerboard. Under DNS I added the outside IPv6 DNS server and enabled ‘Allow Remote Requests’. It didn’t work. Any ideas?

I did not add the %1 to the end of any of the IPv6’s, perhaps thats the deal? I assume that has to do with multicast?

In windows if you set up dual stack then ipv4 dns server can be used to resolve AAAA records.

@changeip
IPv6 multicast addresses are ff00::/8

@hci
fec0::/10 are deprecated ‘site-local’ addresses
In Windows enviroment after ‘%’ is interface index
I also setup HE IPv6 tunnel and there is no problem with DNS on Win7 and WinXP.
Done with RB433AH and ROS 5rc7, so check your config twice.

Regards, Grzegorz.

I tried DNS advertisement between Router OS and Linux. It does work.

Does not work with Windows XP.

Didn’t tried with Seven.


On Windows, you can manually set the DNS through the console using this command :

netsh interface ipv6 add dns [IPv6 address]

By default IPv6 DNS on Windows XP is set to well known unicast addresses :

fec0:0:0:ffff::1
fec0:0:0:ffff::2
fec0:0:0:ffff::3

This is deprecated as those addresses are using site local address space…

Technet say :

“Computers running Windows XP, Windows Server 2003, Windows Vista or Windows Server 2008 can send DNS queries over IPv6 using…”

I never succeeded in sending IPv6 DNS requests from Windows XP. Perhaps is there a hided registry setting ??

Technet article about IPv6 and Windows :

http://technet.microsoft.com/en-us/library/bb726952.aspx


Then in a Microsoft IPv6 FAQ i’ve found :

Even though IPv6 for Windows XP and Windows Server 2003 configures these DNS server addresses and supports the netsh interface ipv6 add dns command, DNS messages are only sent over IPv4.

The FAQ is the truth. Windows XP will certainly get a fix for this in the next monthes before extended support exhaustion.

@FIPTech

Even though IPv6 for Windows XP and Windows Server 2003 configures these DNS server addresses and supports the netsh interface ipv6 add dns command, DNS messages are only sent over IPv4.

You are rirght, I’m in dual-stack mode, my bad :frowning:

Regards, Grzegorz.

I am wanting to do a single stack deployment to test. That way I can see what all works on IPv6 Internet. I know when we deploy to end users we will need to do dual stack but for testing I want to make single stack IPv6 only. Makes it possible to test email and webservers for IPv6 readiness as well.

This is a vey good test.

Unfortunately most OSes and hardware will not pass the test today or will simply not allow to disable IPv4. And most actual softwares will certainly become mad without IPv4 enabled.


Even some standards are missing today to get IPv6 only networks, like IPv6 LDP for MPLS.

So in the mean time we need dual stack everywhere.

@hci

I am wanting to do a single stack deployment to test. That way I can see what all works on IPv6 Internet. I know when we deploy to end users we will need to do dual stack but for testing I want to make single stack IPv6 only. Makes it possible to test email and webservers for IPv6 readiness as well.

Look at HE IPv6 certification, this is practice test and you must configure your web and mail server to be IPv6 ready.
Consider this as some kind of test.

HTH, Grzegorz.

I tried disabling IPv4 on my Windows XP laptop only to find out there is no IPv6 DNS resolving.
I see no IPv6 DNS setting changing possible in Mikrotik ROS. Is there one or does all DNS resolving must go through IPv4 DNS and thus force the use of dual stack IP?

The issue is with your computer, Not ROS.

ROS is sending DNS servers as part of the RA giving your computer it’s IPv6 address however Windows doesn’t currently listen to that info.

To run a pure IPv6 stack on Windows you will have to specify the DNS server for the time being

on my workstation i use “dual stack” everything happens over IPv4 except DNS, as i only have IPv6 address set as DNS name server (my RB asks another RB ipv6 request, and in turn that one asks ipv5 request further) and telnet/ssh/ftp/www management of test routers are ipv6

So - Ubuntu is very ipv6 ready.

Windows XP does not support (yet) DNS over IPv6 transport.

So if you disable IPv4, you can’t have DNS resolution through the system IPv6 stack. Only special programs with internal DNS resolution can work, eventually taking the IPv6 DNS server address in the network settings if you set it.



I hope this will be corrected before Windows XP end of life because this system will stay some years more in business.

I have checked Router Advertisement packet sent by ROS 5_rc8 in the WireShark, but there were no DNS advertise records included. Advertise DNS option is enabled.

I’ve checked this with RC4 it was working with Linux clients.

Broken in RC8 ?

Quick checked it too (rc6) and it advertises DNS servers set in /ip dns. So you have to enter IPv6 address there and it will be passed to clients. It will make clients bypass DNS cache on router. I first expected that the address of the router would be advertised. Maybe you made the same mistake?

But it’s not very useful anyway, AFAIK no version of Windows supports it, including Win7. And Windows is everywhere.

Yes. I checked it now and ROS sends DNS server address in RA, only if the list of DNS servers contains at least one IPv6 address.