"Gary Bennett" wrote:

>The current SOA for the McAfee ftp site, ftp.nai.com, is
>daldc3dns.na.nai.com, which does not resolve to any IP address.
>Periodically, the resolution of ftp.nai.com fails w/this dig result:
>
>; <<>> DiG 9.2.2 <<>> @name.ufl.edu ftp.nai.com
>;; global options: printcmd
>;; Got answer:
>;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11191
>;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
>
>;; QUESTION SECTION:
>;ftp.nai.com. IN A
>
>;; AUTHORITY SECTION:
>ftp.nai.com. 5865 IN SOA daldc3dns.na.nai.com.
>hostmaster.daldc3dns.na.nai.com. 2006032415 28800 7200 604800 86400
>
>;; Query time: 1 msec
>;; SERVER: 128.227.128.24#53(name.ufl.edu)
>;; WHEN: Mon Jun 19 08:22:31 2006
>;; MSG SIZE rcvd: 89
>
>
> After flushing the cache, dig returns:
>
>; <<>> DiG 9.2.2 <<>> ftp.nai.com
>;; global options: printcmd
>;; Got answer:
>;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27866
>;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0
>
>;; QUESTION SECTION:
>;ftp.nai.com. IN A
>
>;; ANSWER SECTION:
>ftp.nai.com. 29 IN A 216.143.70.11
>
>;; AUTHORITY SECTION:
>ftp.nai.com. 82477 IN NS snc3dns.nai.com.
>ftp.nai.com. 82477 IN NS dal3dns.nai.com.
>
>;; Query time: 1 msec
>;; SERVER: 159.178.61.125#53(159.178.61.125)
>;; WHEN: Mon Jun 19 08:24:22 2006
>;; MSG SIZE rcvd: 89
>
>I understand the SOA problem w/the vendor, but the resolver behavior
>still confuses me. Why does it fail, but correct itself after flushing
>the cache? TIA for any suggestions or information. Thanks.
>
>
>gary


In your dig result you have

;; flags: qr rd ra;

There is no "aa", so the answer comes from the cache. Sometime in the
past, the nameserver did a lookup for ftp.nai.com and cached the
negative answer. When you flushed the cache, the nameserver had to
do another lookup for ftp.nai.com; this time it got an answer. I did
the same queries, and I received an answer. I (and dnsreport) see
nothing wrong with the zone that contains ftp.nai.com.
----------------------------------------------------------------------
Barry S. Finkel
Computing and Information Systems Division
Argonne National Laboratory Phone: +1 (630) 252-7277
9700 South Cass Avenue Facsimile:+1 (630) 252-4601
Building 222, Room D209 Internet: BSFinkel@anl.gov
Argonne, IL 60439-4828 IBMMAIL: I1004994