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Date:      Wed, 17 Sep 1997 11:16:32 +0930
From:      Greg Lehey <grog@lemis.com>
To:        FreeBSD Hackers <hackers@freebsd.org>
Subject:   What does this message mean?
Message-ID:  <19970917111632.60309@lemis.com>

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I'm just checking through my DNS logs (4.9.4-REL in current), and I
see a couple of:

Sep 13 10:17:04 freebie named[55]: ns_resp: query(lemis.com) contains our address (FREEBIE.lemis.com:192.109.197.137) learnt (A=198.41.0.4:NS=198.41.0.4)

I checked out the A record; it's a.root-servers.net.  If I interpret
the comments in the source correctly, this is a kind of lame
delegation:

/*
 * if we are being asked to fwd a query whose
 * nameserver list includes our own name/address(es),
 * then we have detected a lame delegation and rather
 * than melt down the network and hose down the other
 * servers (who will hose us in return), we'll return
 * -1 here which will cause SERVFAIL to be sent to
 * the client's resolver which will hopefully then
 * shut up.
 *
 * (originally done in nsContainsUs by vix@dec mar92;
 * moved into nslookup by apb@und jan1993)
 *
 * try to limp along instead of denying service
 * gdonl mar96
 */
 if (aIsUs(nsa)) {
    static char *complaint = "contains our address";
    nslookupComplain(sysloginfo, syslogdname,
                     complaint, dname, dp, nsdp);
    continue;
    }

Can anybody explain this to me in more detail?  Does this mean that
the root name servers are now sending out invalid queries, or are they
just forwarding them from other servers?

Greg




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