nanog mailing list archives
Re: The stupidity of trying to "fix" DHCPv6
From: Jima <nanog () jima tk>
Date: Wed, 15 Jun 2011 10:22:12 -0500
On 06/14/2011 03:25 PM, Leo Bicknell wrote:
I urge everyone in this thread to try a simple experiment. Configure an IPv6 segment in your lab. Make sure there is no IPv4 on it, not on the router, and that the IPv4 stack (to the extent possible) is disabled on the hosts. Now try to use one of the hosts to access IPv6 content.
Been there, done that, fairly happily -- with both Windows 7 and Linux (Fedora 13 or 14, I forget).
You'll find the box does SLAAC just fine and gets an address. You'll find RA's provide a default gateway and can get your packets out to the world. You'll also find absolutely nothing works, at a bare minimum because you have no DNS servers.
Err, no, that's not universally true. The version of NetworkManager in recent-ish Fedora and Ubuntu (can't attest to other distros) supports the RDNSS field in RAs (available in radvd since 1.0, ~2006-11-01). You do need to explicitly disable IPv4 in NM, however, or it'll consider the lack of DHCPv4 to be a general network failure.
RHEL 5 won't work without manually configuring a DNS address; everything I've heard indicates that RHEL 6 supports RDNSS, however.
Windows 7 is a bit of an odd duck; without any defined DNS servers it defaults to the following (deprecated) site-local addresses:
fec0:0:0:ffff::1%1 fec0:0:0:ffff::2%1 fec0:0:0:ffff::3%1Adding a route/config for those on your actual DNS server(s) allows Windows to get working DNS, as well. (I don't recall if I had to explicitly disable IPv4 to get IPv6-only working, though.)
I will agree that Windows XP is more or less dead in the water in your defined scenario (I've heard you can shoehorn IPv6 DNS servers into its config, but it's not trivial; I haven't confirmed this); I haven't tested Vista but I believe its behavior is probably closer to 7 than XP.
The IETF is working on one solution, which is to add DNS information to the RA's! So now you'll configure your routers to hand out DNS servers to clients, and then everything else (NTP servers, Domain Controllers, etc) in DHCP!
Oh, oops; you did touch upon this. You might want to let the people who've implemented RDNSS in software know that the IETF is working on it. I'm sure that'll be a relief.
Jima
Current thread:
- Re: The stupidity of trying to "fix" DHCPv6, (continued)
- Re: The stupidity of trying to "fix" DHCPv6 Ray Soucy (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Nick Hilliard (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Ray Soucy (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Owen DeLong (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Ben Jencks (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Ray Soucy (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Owen DeLong (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Leo Bicknell (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Ben Jencks (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Leo Bicknell (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Jima (Jun 15)
- Re: The stupidity of trying to "fix" DHCPv6 Leo Bicknell (Jun 15)
- Re: The stupidity of trying to "fix" DHCPv6 Iljitsch van Beijnum (Jun 15)
- Re: The stupidity of trying to "fix" DHCPv6 Jima (Jun 15)
- Re: The stupidity of trying to "fix" DHCPv6 Owen DeLong (Jun 16)
- Re: The stupidity of trying to "fix" DHCPv6 Mark Andrews (Jun 16)
- Re: The stupidity of trying to "fix" DHCPv6 Owen DeLong (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Iljitsch van Beijnum (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Ricky Beam (Jun 14)
- RE: The stupidity of trying to "fix" DHCPv6 Dave Edelman (Jun 14)
- Re: The stupidity of trying to "fix" DHCPv6 Owen DeLong (Jun 14)