dns latency

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dns latency

Paul A

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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Re: dns latency

Mark Andrews
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 <[hidden email]> 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
>  
> _______________________________________________
> Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list
>
> bind-users mailing list
> [hidden email]
> https://lists.isc.org/mailman/listinfo/bind-users

--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: [hidden email]

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RE: dns latency

Paul A
Mark, per my previous email, this high latency only happens when digging for
Comcast. I  did not compile bind on this machine, I'm using the latest Bind
package that came with CentOS 7, bind-chroot-9.9.4-73.el7_6.x86_64. Looking
at the changelog for the RPM it doesn't mention any issue with dig and
latency and I assume this has been patched by Redhat at some point.  

I just wanted to verify that what Im seeing with Comcast is somehow not
related to only me and someone else is seeing this issue.  The lastest dig I
did came back with  
"dig: couldn't get address for 'dns101.comcast.net': no more" so I doubt
it's a dig version issue.

Paul


;; Received 239 bytes from 192.5.6.30#53(192.5.6.30) in 32 ms

net.                    172800  IN      NS      k.gtld-servers.net.
net.                    172800  IN      NS      b.gtld-servers.net.
net.                    172800  IN      NS      l.gtld-servers.net.
net.                    172800  IN      NS      a.gtld-servers.net.
net.                    172800  IN      NS      m.gtld-servers.net.
net.                    172800  IN      NS      c.gtld-servers.net.
net.                    172800  IN      NS      i.gtld-servers.net.
net.                    172800  IN      NS      e.gtld-servers.net.
net.                    172800  IN      NS      d.gtld-servers.net.
net.                    172800  IN      NS      g.gtld-servers.net.
net.                    172800  IN      NS      h.gtld-servers.net.
net.                    172800  IN      NS      j.gtld-servers.net.
net.                    172800  IN      NS      f.gtld-servers.net.
net.                    86400   IN      DS      35886 8 2
7862B27F5F516EBE196804
44D4CE5E762981931842C465F00236401D 8BD973EE
net.                    86400   IN      RRSIG   DS 8 1 86400 20190425050000
2019
0412040000 25266 . Uk5bsrr1dgoBFUYfzSYTi6D+QXow1CZglnE3BUZ7I/I0HjuywiSf2YLx
eU1c
rjlYOJQdYPxDFQIH5/aItTtrM7wgvTOhfhHPHQuAj2f8ovYIlwCt
hguq+9jcNTMAzrUXvi6Tb8oTb36
lprYIfg21yO1d8RO6cx3L0dJMcuez
WN2kxNAg+wrx+dWbOexFO7Hs0gzDPpsMx0lEOkJHcfyb/V71An
MV+nob 48G/azRzQ2fJfs849OyYmjTXA88bAcxxz3kNCoddOfWuMU+WKV5Lfy7J
NkegEfRCzRZYYKiD
MwI0zURTg+CdZAYKuxvJQW9ddzSiK5UnYXZVSO1d fPXfYQ==
;; Received 1168 bytes from 199.9.14.201#53(b.root-servers.net) in 88 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
30C0F50E68DCC9A2F279A9
94C07CF22CED97AADF44C2B1FE38A1B32B A1A34174
comcast.net.            86400   IN      DS      40909 5 1
DDC19733884EE533B35B4B
57717BEA9B0EF2C4D1
comcast.net.            86400   IN      RRSIG   DS 8 2 86400 20190417054136
2019
0410043136 51638 net.
l2Vj2W+qzAziqzcC+Y+t4+6b6ADTwyILCzbySVmj5mj5J9vscR4mYf+f X
zNGKen73GecLw+HiwwSzUG8jYkGtvNOMrj9ZbC4v+XWuq0EFcxDEhbJ
yTAq2wPMGD6evSUSDLfqYu8h
oJH9svqS06KlBjWkKQqx8X+ZIIqmUMVk ivk=
dig: couldn't get address for 'dns101.comcast.net': no more

-----Original Message-----
From: Mark Andrews [mailto:[hidden email]]
Sent: Friday, April 12, 2019 11:20 AM
To: Paul A <[hidden email]>
Cc: [hidden email] <[hidden email]>
Subject: Re: dns latency

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 <[hidden email]> 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
>  
> _______________________________________________
> Please visit https://lists.isc.org/mailman/listinfo/bind-users to
> unsubscribe from this list
>
> bind-users mailing list
> [hidden email]
> https://lists.isc.org/mailman/listinfo/bind-users

--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: [hidden email]

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Re: dns latency

Bob Harold

On Fri, Apr 12, 2019 at 12:37 PM Paul A <[hidden email]> wrote:
Mark, per my previous email, this high latency only happens when digging for
Comcast. I  did not compile bind on this machine, I'm using the latest Bind
package that came with CentOS 7, bind-chroot-9.9.4-73.el7_6.x86_64. Looking
at the changelog for the RPM it doesn't mention any issue with dig and
latency and I assume this has been patched by Redhat at some point. 

I just wanted to verify that what Im seeing with Comcast is somehow not
related to only me and someone else is seeing this issue.  The lastest dig I
did came back with 
"dig: couldn't get address for 'dns101.comcast.net': no more" so I doubt
it's a dig version issue.

Paul


;; Received 239 bytes from 192.5.6.30#53(192.5.6.30) in 32 ms

net.                    172800  IN      NS      k.gtld-servers.net.
net.                    172800  IN      NS      b.gtld-servers.net.
net.                    172800  IN      NS      l.gtld-servers.net.
net.                    172800  IN      NS      a.gtld-servers.net.
net.                    172800  IN      NS      m.gtld-servers.net.
net.                    172800  IN      NS      c.gtld-servers.net.
net.                    172800  IN      NS      i.gtld-servers.net.
net.                    172800  IN      NS      e.gtld-servers.net.
net.                    172800  IN      NS      d.gtld-servers.net.
net.                    172800  IN      NS      g.gtld-servers.net.
net.                    172800  IN      NS      h.gtld-servers.net.
net.                    172800  IN      NS      j.gtld-servers.net.
net.                    172800  IN      NS      f.gtld-servers.net.
net.                    86400   IN      DS      35886 8 2
7862B27F5F516EBE196804
44D4CE5E762981931842C465F00236401D 8BD973EE
net.                    86400   IN      RRSIG   DS 8 1 86400 20190425050000
2019
0412040000 25266 . Uk5bsrr1dgoBFUYfzSYTi6D+QXow1CZglnE3BUZ7I/I0HjuywiSf2YLx
eU1c
rjlYOJQdYPxDFQIH5/aItTtrM7wgvTOhfhHPHQuAj2f8ovYIlwCt
hguq+9jcNTMAzrUXvi6Tb8oTb36
lprYIfg21yO1d8RO6cx3L0dJMcuez
WN2kxNAg+wrx+dWbOexFO7Hs0gzDPpsMx0lEOkJHcfyb/V71An
MV+nob 48G/azRzQ2fJfs849OyYmjTXA88bAcxxz3kNCoddOfWuMU+WKV5Lfy7J
NkegEfRCzRZYYKiD
MwI0zURTg+CdZAYKuxvJQW9ddzSiK5UnYXZVSO1d fPXfYQ==
;; Received 1168 bytes from 199.9.14.201#53(b.root-servers.net) in 88 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
30C0F50E68DCC9A2F279A9
94C07CF22CED97AADF44C2B1FE38A1B32B A1A34174
comcast.net.            86400   IN      DS      40909 5 1
DDC19733884EE533B35B4B
57717BEA9B0EF2C4D1
comcast.net.            86400   IN      RRSIG   DS 8 2 86400 20190417054136
2019
0410043136 51638 net.
l2Vj2W+qzAziqzcC+Y+t4+6b6ADTwyILCzbySVmj5mj5J9vscR4mYf+f X
zNGKen73GecLw+HiwwSzUG8jYkGtvNOMrj9ZbC4v+XWuq0EFcxDEhbJ
yTAq2wPMGD6evSUSDLfqYu8h
oJH9svqS06KlBjWkKQqx8X+ZIIqmUMVk ivk=
dig: couldn't get address for 'dns101.comcast.net': no more

-----Original Message-----
From: Mark Andrews [mailto:[hidden email]]
Sent: Friday, April 12, 2019 11:20 AM
To: Paul A <[hidden email]>
Cc: [hidden email] <[hidden email]>
Subject: Re: dns latency

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 <[hidden email]> 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

> _______________________________________________
> Please visit https://lists.isc.org/mailman/listinfo/bind-users to
> unsubscribe from this list
>
> bind-users mailing list
> [hidden email]
> https://lists.isc.org/mailman/listinfo/bind-users

--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: [hidden email]



I get 57ms max for the various gtld servers.  Could you try this:

for x in a b c d e f g h i j k l m; do echo "==== $x ===="; dig comcast.net. +norec +noall +auth +stats @$x.gtld-servers.net.; done

-- 
Bob Harold
 

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RE: dns latency

Paul A
Bob,

I get no real latency doing this, previously I was pinging the GTLD with the high latency from the query and I was not seeing any latency with ping, thus why I emailed the list.
Currently doing a dig +trace on comcast.net sees no issues, but per my emails below, there was high latency from the GLTD to comcast’s DNS I even got, dig: couldn't get address for 'dns101.comcast.net': no more at one point. Although now it seems to be back to normal, not sure what to make of it.

 Thanks for your reply Bob.

Paul


==== a ====
;; Query time: 26 msec
==== b ====
;; Query time: 172 msec
==== c ====
;; Query time: 26 msec
==== d ====
;; Query time: 26 msec
==== e ====
;; Query time: 76 msec
==== f ====
;; Query time: 76 msec
==== g ====
;; Query time: 75 msec
==== h ====
;; Query time: 8 msec
==== i ====
;; Query time: 8 msec
==== j ====
;; Query time: 8 msec
==== k ====
;; Query time: 38 msec
==== l ====
;; Query time: 38 msec
==== m ====
;; Query time: 38 msec

From: Bob Harold [mailto:[hidden email]]
Sent: Friday, April 12, 2019 12:52 PM
To: Paul A <[hidden email]>
Cc: Mark Andrews <[hidden email]>; [hidden email] <[hidden email]>
Subject: Re: dns latency


On Fri, Apr 12, 2019 at 12:37 PM Paul A <[hidden email]> wrote:
Mark, per my previous email, this high latency only happens when digging for
Comcast. I  did not compile bind on this machine, I'm using the latest Bind
package that came with CentOS 7, bind-chroot-9.9.4-73.el7_6.x86_64. Looking
at the changelog for the RPM it doesn't mention any issue with dig and
latency and I assume this has been patched by Redhat at some point.  

I just wanted to verify that what Im seeing with Comcast is somehow not
related to only me and someone else is seeing this issue.  The lastest dig I
did came back with  
"dig: couldn't get address for 'dns101.comcast.net': no more" so I doubt
it's a dig version issue.

Paul


;; Received 239 bytes from 192.5.6.30#53(192.5.6.30) in 32 ms

net.                    172800  IN      NS      k.gtld-servers.net.
net.                    172800  IN      NS      b.gtld-servers.net.
net.                    172800  IN      NS      l.gtld-servers.net.
net.                    172800  IN      NS      a.gtld-servers.net.
net.                    172800  IN      NS      m.gtld-servers.net.
net.                    172800  IN      NS      c.gtld-servers.net.
net.                    172800  IN      NS      i.gtld-servers.net.
net.                    172800  IN      NS      e.gtld-servers.net.
net.                    172800  IN      NS      d.gtld-servers.net.
net.                    172800  IN      NS      g.gtld-servers.net.
net.                    172800  IN      NS      h.gtld-servers.net.
net.                    172800  IN      NS      j.gtld-servers.net.
net.                    172800  IN      NS      f.gtld-servers.net.
net.                    86400   IN      DS      35886 8 2
7862B27F5F516EBE196804
44D4CE5E762981931842C465F00236401D 8BD973EE
net.                    86400   IN      RRSIG   DS 8 1 86400 20190425050000
2019
0412040000 25266 . Uk5bsrr1dgoBFUYfzSYTi6D+QXow1CZglnE3BUZ7I/I0HjuywiSf2YLx
eU1c
rjlYOJQdYPxDFQIH5/aItTtrM7wgvTOhfhHPHQuAj2f8ovYIlwCt
hguq+9jcNTMAzrUXvi6Tb8oTb36
lprYIfg21yO1d8RO6cx3L0dJMcuez
WN2kxNAg+wrx+dWbOexFO7Hs0gzDPpsMx0lEOkJHcfyb/V71An
MV+nob 48G/azRzQ2fJfs849OyYmjTXA88bAcxxz3kNCoddOfWuMU+WKV5Lfy7J
NkegEfRCzRZYYKiD
MwI0zURTg+CdZAYKuxvJQW9ddzSiK5UnYXZVSO1d fPXfYQ==
;; Received 1168 bytes from 199.9.14.201#53(b.root-servers.net) in 88 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
30C0F50E68DCC9A2F279A9
94C07CF22CED97AADF44C2B1FE38A1B32B A1A34174
comcast.net.            86400   IN      DS      40909 5 1
DDC19733884EE533B35B4B
57717BEA9B0EF2C4D1
comcast.net.            86400   IN      RRSIG   DS 8 2 86400 20190417054136
2019
0410043136 51638 net.
l2Vj2W+qzAziqzcC+Y+t4+6b6ADTwyILCzbySVmj5mj5J9vscR4mYf+f X
zNGKen73GecLw+HiwwSzUG8jYkGtvNOMrj9ZbC4v+XWuq0EFcxDEhbJ
yTAq2wPMGD6evSUSDLfqYu8h
oJH9svqS06KlBjWkKQqx8X+ZIIqmUMVk ivk=
dig: couldn't get address for 'dns101.comcast.net': no more

-----Original Message-----
From: Mark Andrews [mailto:[hidden email]]
Sent: Friday, April 12, 2019 11:20 AM
To: Paul A <[hidden email]>
Cc: [hidden email] <[hidden email]>
Subject: Re: dns latency

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 <[hidden email]> 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: [hidden email]


I get 57ms max for the various gtld servers.  Could you try this:

for x in a b c d e f g h i j k l m; do echo "==== $x ===="; dig comcast.net. +norec +noall +auth +stats @$x.gtld-servers.net.; done

--
Bob Harold
 

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