Internet Unknown (28)
Jonathan de Boyne Pollard
J.deBoynePollard at Tesco.NET
Thu Nov 18 04:43:29 UTC 2004
MA> The polaris.co.in nameservers are not RFC 1034 compliant (they don't
MA> reply to EDNS (RFC 2671) queries).
Not replying to queries is not a violation of the protocol. There's no
way that any protocol (such as DNS) that employs an unreliable transport
(such as UDP) can make replying to messages a requirement. It's wrong
to say that a server that doesn't reply to queries is not complying with
MA> You would think that all nameservers would handle EDNS queries by
MA> now. After all EDNS has been on the standards track for 5 years now.
The situation with EDNS0 is that because so few content DNS servers
support it, the gain that EDNS0 gives from losing the DNS/TCP
setup/teardown overhead in the small minority of cases is entirely
offset by the loss incurred by the extra DNS/UDP traffic in the vast
majority of cases.
As I have said before, the irony of this is that support for EDNS0 in
content DNS servers is comparatively easy compared to support for EDNS0
in the back ends of resolving proxy DNS servers and in DNS Client
libraries. If everyone merely did only the easy part of implementing
EDNS0 support in their content DNS servers (even if only supporting
DNS/UDP datagram sizes up to 512 octets), the current situation would be
much improved, and enabling the use of EDNS0 in a resolving proxy DNS
server would no longer result in a net increase in network traffic.
MA> It only takes 1/2 a day to add support for them to a existing
That's a facile assertion. How long it takes to add EDNS0 support
obviously depends from the particular server software. As I said, it
also depends from the type of the server software.
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