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help please - i think my DNS is broken

KEVIN MCCOY
Level 1
Level 1

 

DNS issue

so i am new to DNS, here is my problem, we have cisco umbrella forwarders on all our DNS servers

we have a marketing site hosted, externally the site works perfect however lately internally when we hit the url we get page cannot be displayed, the fix is to go to our DNS servers and clear cache which works for about 30 minutes then it breaks again
 
4 Replies 4

marce1000
VIP
VIP

 

 - Difficult to tell, in a first debugging step remove Umbrella from the DNS setup and start using the DNS servers from the  ISP. Check whether the problem then remains in place or not.

M.



-- Each morning when I wake up and look into the mirror I always say ' Why am I so brilliant ? '
    When the mirror will then always repond to me with ' The only thing that exceeds your brilliance is your beauty! '

CSCO11304974
Level 1
Level 1
Command prompt
---------------------
#Sh ip config
Ping the primary DNS and Secondary DNS
Both DNS ping means there is no issue with ISP , not pinging means issue with ISP.

Thanks,
Praveen.N

pieterh
VIP
VIP

please collect some more information

1) if the site works what IP address is resolved?

2) if it does not work what IP addres is in the cache?

3) what is the SOA (primary DNS) of this domain?

4) where comes the timeout of 30 min from?
    (it may be this is the TTL of the dns-record that is too short)

looks like it was an issue on Cisco Umbrella side

 

 


Mash Sarband (Umbrella)
Nov 16, 14:12 PST

Anyone that used us as a DNS resolver. We will provide you with more infromation after we receive the RCA.

Mash Sarband

Regional Technical Support Manager (US west)
Cisco Umbrella


Nov 16, 14:07 PST

Thanks Mash, is this affecting all Cisco Umbrella customers or only a particular set?

-------- Original message --------

      
Mash Sarband (Umbrella)
Nov 16, 14:05 PST

Hi 

We have asked for a Root Cause Analysis from our engineers and will update you as soon as we hear back.

Best regards,

Mash Sarband

Regional Technical Support Manager (US west)
Cisco Umbrella

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