www.cisco.com no resolve?

Mailman List Mirror (Read Only)
1

dig www.cisco.com @8.8.8.8

; <<>> DiG 9.8.3-P1 <<>> www.cisco.com @8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 60416
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;www.cisco.com. IN A

;; AUTHORITY SECTION:
cisco.com. 1247 IN SOA edns-rtp5-1-l. postmaster.cisco.com. 16034550 7200 1800 864000 86400

;; Query time: 94 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Sat Mar 19 07:36:22 2016
;; MSG SIZE rcvd: 91

2

Confirmed in Northern California, on all 3 primary NS servers. A little Friday night maintenance window, maybe?

Looks like it’s just the www record...

3

Hi,

Here is the dig results, yes it seems only happened to www

gizmos:~ david$ dig www.cisco.com +trace

; <<>> DiG 9.8.3-P1 <<>> www.cisco.com +trace

;; global options: +cmd

. 131 IN NS c.root-servers.net.

. 131 IN NS d.root-servers.net.

. 131 IN NS i.root-servers.net.

. 131 IN NS l.root-servers.net.

. 131 IN NS a.root-servers.net.

. 131 IN NS f.root-servers.net.

. 131 IN NS k.root-servers.net.

. 131 IN NS b.root-servers.net.

. 131 IN NS m.root-servers.net.

. 131 IN NS e.root-servers.net.

. 131 IN NS j.root-servers.net.

. 131 IN NS h.root-servers.net.

. 131 IN NS g.root-servers.net.

;; Received 228 bytes from 103.234.208.150#53(103.234.208.150) in 2473 ms

com. 172800 IN NS a.gtld-servers.net.

com. 172800 IN NS b.gtld-servers.net.

com. 172800 IN NS c.gtld-servers.net.

com. 172800 IN NS d.gtld-servers.net.

com. 172800 IN NS e.gtld-servers.net.

com. 172800 IN NS f.gtld-servers.net.

com. 172800 IN NS g.gtld-servers.net.

com. 172800 IN NS h.gtld-servers.net.

com. 172800 IN NS i.gtld-servers.net.

com. 172800 IN NS j.gtld-servers.net.

com. 172800 IN NS k.gtld-servers.net.

com. 172800 IN NS l.gtld-servers.net.

com. 172800 IN NS m.gtld-servers.net.

;; Received 491 bytes from 198.97.190.53#53(198.97.190.53) in 799 ms

cisco.com. 172800 IN NS ns1.cisco.com.

cisco.com. 172800 IN NS ns2.cisco.com.

cisco.com. 172800 IN NS ns3.cisco.com.

;; Received 217 bytes from 192.26.92.30#53(192.26.92.30) in 1197 ms

cisco.com. 86400 IN SOA edns-rtp5-1-l. postmaster.cisco.com. 16034550 7200
1800 864000 86400

;; Received 91 bytes from 72.163.5.201#53(72.163.5.201) in 243 ms

gizmos:~ david$ dig cisco.com +trace

; <<>> DiG 9.8.3-P1 <<>> cisco.com +trace

;; global options: +cmd

. 120 IN NS b.root-servers.net.

. 120 IN NS c.root-servers.net.

. 120 IN NS j.root-servers.net.

. 120 IN NS e.root-servers.net.

. 120 IN NS m.root-servers.net.

. 120 IN NS l.root-servers.net.

. 120 IN NS h.root-servers.net.

. 120 IN NS a.root-servers.net.

. 120 IN NS g.root-servers.net.

. 120 IN NS k.root-servers.net.

. 120 IN NS i.root-servers.net.

. 120 IN NS d.root-servers.net.

. 120 IN NS f.root-servers.net.

;; Received 228 bytes from 103.234.208.150#53(103.234.208.150) in 48 ms

com. 172800 IN NS d.gtld-servers.net.

com. 172800 IN NS l.gtld-servers.net.

com. 172800 IN NS g.gtld-servers.net.

com. 172800 IN NS e.gtld-servers.net.

com. 172800 IN NS b.gtld-servers.net.

com. 172800 IN NS c.gtld-servers.net.

com. 172800 IN NS k.gtld-servers.net.

com. 172800 IN NS i.gtld-servers.net.

com. 172800 IN NS m.gtld-servers.net.

com. 172800 IN NS j.gtld-servers.net.

com. 172800 IN NS f.gtld-servers.net.

com. 172800 IN NS h.gtld-servers.net.

com. 172800 IN NS a.gtld-servers.net.

;; Received 499 bytes from 192.36.148.17#53(192.36.148.17) in 41 ms

cisco.com. 172800 IN NS ns1.cisco.com.

cisco.com. 172800 IN NS ns2.cisco.com.

cisco.com. 172800 IN NS ns3.cisco.com.

;; Received 213 bytes from 192.31.80.30#53(192.31.80.30) in 355 ms

cisco.com. 86400 IN A 72.163.4.161

cisco.com. 86400 IN NS ns2.cisco.com.

cisco.com. 86400 IN NS ns3.cisco.com.

cisco.com. 86400 IN NS ns1.cisco.com.

;; Received 229 bytes from 72.163.5.201#53(72.163.5.201) in 415 ms

Thank you

Best regards,
David S.

4

a message of 49 lines which said:

Confirmed in Northern California, on all 3 primary NS servers. A
little Friday night maintenance window, maybe?

Isn't it simply because the alias chain is awfully long (five steps)
and it may fail with resolvers which are hardened against the
"infinite recursion" attack?

% dig A www.cisco.com
...
;; ANSWER SECTION:
www.cisco.com. 3538 IN CNAME www.cisco.com.akadns.net.
www.cisco.com.akadns.net. 238 IN CNAME wwwds.cisco.com.edgekey.net.
wwwds.cisco.com.edgekey.net. 21538 IN CNAME wwwds.cisco.com.edgekey.net.globalredir.akadns.net.
wwwds.cisco.com.edgekey.net.globalredir.akadns.net. 3538 IN CNAME e144.dscb.akamaiedge.net.
e144.dscb.akamaiedge.net. 20 IN A 104.93.242.137

http://www.ssi.gouv.fr/uploads/2014/12/idns_attack_anssi.pdf

5

a message of 13 lines which said:

dig www.cisco.com @8.8.8.8

Better to test through the authoritative name servers. The problem was
there, as documented in
<https://www.reddit.com/r/networking/comments/4b2bgo/cisco_website_is_down/d15iu63&gt;

So, it was not because of the long CNAME chain, unlike what I wrote
previously.

6

They did announce a maintenance window on their website.
Must have been a doozy.