Subject: RE: You saw this, right?

From: Bill Woodcock <[email-masked]>
Date: Mon, 26 Jun 2006 10:05:01 -0700 (PDT)

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    > What I was thinking was, assume you have N anycast hosts who are DNS
    > servers and all receive DNS queries sent to IP address ADDR-0.

All are capable of receiving, but only one actually receives any specific 
query...

    > If they really all think they are just a host at address ADDR-0 and 
    > any of these host sends out a DNS query, presumably the anycast 
    > nature of their address would mean that the response to that query 
    > could come back to a different one than the host which originated 
    > the query.

Ah, I see what you were getting at.  In practice, one never originates a 
transaction with the anycast address as source.  One only originates 
transactions from the host's unique address.  In practice, the anycast 
service addresses are loopbacks internal to the host, while the actual 
physical interfaces which are used to originate transactions use the 
host's unique addresses.

So this is never actually a problem.  I suppose in the interests of 
thoroughness, it wouldn't hurt to explain why, so new people don't have to 
stub their toes on that same corner-case.

                                -Bill

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---

From: Bill Woodcock <[email-masked]>
Date: Mon, 26 Jun 2006 09:14:04 -0700 (PDT)

>    Anycast accessed servers are
    >    unlikely to be recursive servers or otherwise act as resolvers due to
    >    the confusion that would result in getting responses to their queries
    >    back to the right machine.

Hi, Donald.  

We're having king of  hard time figuring out what you're getting at here.  
Care to clarify it?

                                -Bill