SUMMARY Re: Weird DNS problem

From: Joe Welfeld (
Date: Wed Sep 13 1995 - 14:12:12 CDT

Thanks to all who responded, (See below):

Original question (shortened):

 We just started having a problem with mail to and from
 Compuserve. It seems sendmail cores. We spoke with
 Compuserve and they informed us that they just did a
 major update to their DNS.
 When I use nslookup on I also get a core,
 I figure it must be the same, or similar problem. We are
 running SunOS 4.1.3 and in.named as our DNS server.

The answer (from Larry J. Blunk) is:

        This is a bug in Sun's DNS resolver support under NIS.
        It can't handle large numbers of A records for a name
        (this is completely legal, by the way, and is done for
        either redundancy or load-sharing).

        You need the libc jumbo patch. It's 100891-12 for
        SunOS 4.1.3 and 101558-06 for SunOS 4.1.3_U1.

        You could also get around Sun's bug by changing the
        way the DNS data is configured. We use multiple CNAMEs
        for a name with each CNAME pointing to multiple A records.
        It's kind of kludge, but it gets arounds Sun's bug. You
        have to ask CompuServe to make this change.

The problem has (temporarily) dissapeared, due to caching of
DNS data by the name server. As soon as the cache gets flushed,
and we get an Authoritative answer from compuserve the problem

I have not installed this patch but am planning on doing it today.

Thanks to:

"Larry J. Blunk" <> (Rahul Roy)
Henry Katz <> (Jim Murff)

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