dns latency
Mark Andrews
marka at isc.org
Fri Apr 12 15:19:55 UTC 2019
Before you pay attention to the round trip time you need this fix from BIND 9.9.6
from nearly 5 years ago now (2014-07-31).
3903. [bug] Improve the accuracy of DiG's reported round trip
time. [RT 36611]
Mark
> On 13 Apr 2019, at 12:59 am, Paul A <razor at meganet.net> wrote:
>
> This is not really a Bind issue, but can anyone else confirm latency when querying Comcast from the root down? I ask because this morning some of our customers
> Could not email @comcast addresses, looked at the mail server and domain not found. I suspect my cache for Comcast timeout and when my DNS server tried doing a new query it timeout on GTLD server to Comcast?
>
> When I query directly to their DNS servers there is no latency, so I suspect this is a link issue at Comcast affecting DNS?
>
> TIA paul
>
>
>
> ; <<>> DiG 9.9.4-RedHat-9.9.4-61.el7_5.1 <<>> @192.5.6.30 comcast.net -t a +trace
> ; (1 server found)
> ;; global options: +cmd
> . 518400 IN NS i.root-servers.net.
> . 518400 IN NS j.root-servers.net.
> . 518400 IN NS k.root-servers.net.
> . 518400 IN NS l.root-servers.net.
> . 518400 IN NS m.root-servers.net.
> . 518400 IN NS a.root-servers.net.
> . 518400 IN NS b.root-servers.net.
> . 518400 IN NS c.root-servers.net.
> . 518400 IN NS d.root-servers.net.
> . 518400 IN NS e.root-servers.net.
> . 518400 IN NS f.root-servers.net.
> . 518400 IN NS g.root-servers.net.
> . 518400 IN NS h.root-servers.net.
> ;; Received 239 bytes from 192.5.6.30#53(192.5.6.30) in 32 ms
>
> net. 172800 IN NS a.gtld-servers.net.
> net. 172800 IN NS b.gtld-servers.net.
> net. 172800 IN NS c.gtld-servers.net.
> net. 172800 IN NS d.gtld-servers.net.
> net. 172800 IN NS e.gtld-servers.net.
> net. 172800 IN NS f.gtld-servers.net.
> net. 172800 IN NS g.gtld-servers.net.
> net. 172800 IN NS h.gtld-servers.net.
> net. 172800 IN NS i.gtld-servers.net.
> net. 172800 IN NS j.gtld-servers.net.
> net. 172800 IN NS k.gtld-servers.net.
> net. 172800 IN NS l.gtld-servers.net.
> net. 172800 IN NS m.gtld-servers.net.
> net. 86400 IN DS 35886 8 2 7862B27F5F516EBE19680444D4CE5E762981931842C465F00236401D 8BD973EE
> net. 86400 IN RRSIG DS 8 1 86400 20190425050000 20190412040000 25266 . Uk5bsrr1dgoBFUYfzSYTi6D+QXow1CZglnE3BUZ7I/I0HjuywiSf2YLx eU1crjlYOJQdYPxDFQIH5/aItTtrM7wgvTOhfhHPHQuAj2f8ovYIlwCt hguq+9jcNTMAzrUXvi6Tb8oTb36lprYIfg21yO1d8RO6cx3L0dJMcuez WN2kxNAg+wrx+dWbOexFO7Hs0gzDPpsMx0lEOkJHcfyb/V71AnMV+nob 48G/azRzQ2fJfs849OyYmjTXA88bAcxxz3kNCoddOfWuMU+WKV5Lfy7J NkegEfRCzRZYYKiDMwI0zURTg+CdZAYKuxvJQW9ddzSiK5UnYXZVSO1d fPXfYQ==
> ;; Received 1168 bytes from 198.97.190.53#53(h.root-servers.net) in 19 ms
>
> comcast.net. 172800 IN NS dns101.comcast.net.
> comcast.net. 172800 IN NS dns102.comcast.net.
> comcast.net. 172800 IN NS dns103.comcast.net.
> comcast.net. 172800 IN NS dns104.comcast.net.
> comcast.net. 172800 IN NS dns105.comcast.net.
> comcast.net. 86400 IN DS 40909 5 2 30C0F50E68DCC9A2F279A994C07CF22CED97AADF44C2B1FE38A1B32B A1A34174
> comcast.net. 86400 IN DS 40909 5 1 DDC19733884EE533B35B4B57717BEA9B0EF2C4D1
> comcast.net. 86400 IN RRSIG DS 8 2 86400 20190417054136 20190410043136 51638 net. l2Vj2W+qzAziqzcC+Y+t4+6b6ADTwyILCzbySVmj5mj5J9vscR4mYf+f XzNGKen73GecLw+HiwwSzUG8jYkGtvNOMrj9ZbC4v+XWuq0EFcxDEhbJ yTAq2wPMGD6evSUSDLfqYu8hoJH9svqS06KlBjWkKQqx8X+ZIIqmUMVk ivk=
> ;; Received 612 bytes from 192.42.93.30#53(g.gtld-servers.net) in 25090 ms
>
> comcast.net. 30 IN A 69.252.80.75
> comcast.net. 30 IN RRSIG A 5 2 30 20190418174157 20190411143657 26550 comcast.net. YegwZlzjBoJ+b9nWTHwRZQbce619UcOVdo6FUPG056Sod4MEchv/GCHu 7BpREAUm0CBoE4qbipTiS47wIk7QJYzz10B78wRgMGNwMTUXQ571YRyq P0I3I0Dzag28j607walJOZms3lAXDzSnyvv9wocaH2MJ7Z3j68Qf5pKh YpM=
> ;; Received 227 bytes from 69.252.250.103#53(dns101.comcast.net) in 14 ms
>
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--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka at isc.org
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