Hi List, Is there anyone on the list from Cisco managing cisco.com?
I have observed a reproducible issue that is as follows: - I have a small DNS server running which does recursive resolution over local private network and also hosts some live zones for testing and experiments. - When I visit cisco.com, my DNS server does the recursive resolution and things work as expected i.e. the website loads, except that 3 IP addresses from Cisco start querying back to my DNS server indefinitely. It continues for hours and I have seen it from logs that it was doing so for 18 hrs. It stops when the DNS server stops responding which I found out by taking the DNS server "offline" by removing inbound port forwarding rules on router for few minutes. - The 3 Cisco IP addresses that keep querying indefinitely are: - 173.37.149.230 [alln01-ucs-dcz03n-cnt-gslb3-snip.cisco.com] - 72.163.5.22 [rcdn9-ucs-dcz05n-cnt-gslb3-snip.cisco.com] - 64.101.37.86 - All the queries from these 3 IP addresses are same: QNAME: . QTYPE: A CLASS: IN - The DNS server returns response with RCODE: Refused - The overall query rate for all these IP addresses combined is exactly 23 queries per minute. I have successfully reproduced this issue twice by visiting cisco.com which triggers it immediately. I believe there is something really wrong that needs fixing. Regards, *Shreyas Zare* Technitium <https://technitium.com>
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