[Dnsmasq-discuss] Windows ipv6 hostname

[Markus Hartung]

On 2016-12-22 13:48, Pali Rohár wrote:
> Windows Vista has (good quality) support for DHCPv6 and IIRC new
> versions of Windowses uses same/similar implementation. So I think
> Windows 10 should work (no idea if some advanced configuration is
> needed)... Also at that time Windows Vista had correct implementation of
> using RA prefix together with assigned DHCPv6 address. (In contrast
> common linux ISC DHCPv6 client is still broken and hardcode /64 prefix
> even if RA announce different).
Allright, hope they haven't screwed up anything in later versions of 
windows.

> It is common behaviour that all firewalls block everything except some
> exceptions. It is also good for security reasons.
>
> DHCP is using IPv4 and DHCPv6 is obviously using IPv6. And IPv6 network
> stack is independent of IPv4, so you need to configure your firewall
> differently for IPv4 and IPv6 (e.g. iptables vs. ip6tables).
>
> And because DHCP and DHCPv6 are *different* protocols, they should not
> be used on same ports. If you look at DNS there is no DNSv6 or so. DNS
> is same over IPv4 and IPv6.
>
> You cannot ask for IPv6 address via DHCP or IPv4 via DHCPv6. But you can
> resolve AAAA record (IPv6) via IPv4 connection to DNS, so hence DNS is
> only one.
>
> If you cannot memorize number of tcp or udp ports for some services,
> just look into /etc/services file.
>
> $ grep -E -i 'dhcp|bootp' /etc/services
> bootps          67/tcp                          # BOOTP server
> bootps          67/udp
> bootpc          68/tcp                          # BOOTP client
> bootpc          68/udp
> dhcpv6-client   546/tcp
> dhcpv6-client   546/udp
> dhcpv6-server   547/tcp
> dhcpv6-server   547/udp
>
  Thanks for the insight. There were no rules in ufw about dhcp-client 
and server, my guess is that most want ipv4 and most doesn't care/know 
about ipv6.
> I remember that Windowses act differently if they are configured to be
> part of domain or if they have set some domain name or if they have
> configured some workgroup or if they have enabled sharing for small home
> networks... This is just my observation and maybe one of those settings
> is different on working and non working host?
>
> I could not help you with Windows 10, but try to look at different
> network settings in Windows. Maybe you find something...
I have windows 10 pro on the working host and "only" windows 10 home on 
the non-working. Perhaps the home version it's assumed that the dhcp 
server is just handling dhcp for a few hosts and therefore the 
dns-handling is to be handled by the dns-server via a "dynamic update" 
message to the dns-server (which dnsmasq claims to not support).

And on pro version it is assumed to have more infrastructure in the dhcp 
server.

Just a theory though. I can try install a home version in a virtual 
machine and test out the hypothesis. I'm going to see if I can upgrade 
my home to pro if that is the issue.


BR,
Markus