resolving www.ecb.europa.eu tages ages
Robert M. Stockmann
stock at stokkie.net
Mon Jun 20 13:27:41 UTC 2022
On Fri, 17 Jun 2022, Matus UHLAR - fantomas wrote:
> Date: Fri, 17 Jun 2022 13:04:51 +0200
> From: Matus UHLAR - fantomas <uhlar at fantomas.sk>
> To: bind-users at lists.isc.org
> Subject: resolving www.ecb.europa.eu tages ages
>
> Hello,
>
> I encountered case where resolution of www.ecb.europa.eu takes long time and
> I can't find out why.
>
> I'm trying to find the culprit using dig +trace and resolution times change
> from < 1 second to > 15 seconds, while response times reported by dig say
> miliseconds.
>
> multiple runs of dig seem to fix the issue until I clear named cache.
> (which indicated problem is in DNS, but I still have no idea where)
>
> I'm out od ideas what to search for.
>
> I have debian 11 with bind version 1:9.16.27-1~deb11u1
>
> an example dig that took 5 seconds pasted:
>
> # time dig +trace www.ecb.europa.eu
>
> ; <<>> DiG 9.16.27-Debian <<>> +trace www.ecb.europa.eu
> ;; global options: +cmd
> . 194472 IN NS m.root-servers.net.
> . 194472 IN NS k.root-servers.net.
> . 194472 IN NS f.root-servers.net.
> ----//--------
> www.ecb.europa.eu. 300 IN CNAME www-ecb-europa-eu.ax4z.com.
> ;; Received 86 bytes from 156.154.65.109#53(pdns109.ultradns.net) in 11 ms
>
> real 0m5.117s
> user 0m0.011s
> sys 0m0.035s
> ======================
Here's what i get :
$ time dig +trace www.ecb.europa.eu
; <<>> DiG 9.8.1 <<>> +trace www.ecb.europa.eu
;; global options: +cmd
. 6453 IN NS i.root-servers.net.
. 6453 IN NS b.root-servers.net.
. 6453 IN NS c.root-servers.net.
. 6453 IN NS j.root-servers.net.
. 6453 IN NS k.root-servers.net.
. 6453 IN NS l.root-servers.net.
. 6453 IN NS a.root-servers.net.
. 6453 IN NS g.root-servers.net.
. 6453 IN NS d.root-servers.net.
. 6453 IN NS f.root-servers.net.
. 6453 IN NS m.root-servers.net.
. 6453 IN NS e.root-servers.net.
. 6453 IN NS h.root-servers.net.
;; Received 228 bytes from 192.168.188.10#53(192.168.188.10) in 134 ms
eu. 172800 IN NS w.dns.eu.
eu. 172800 IN NS x.dns.eu.
eu. 172800 IN NS y.dns.eu.
eu. 172800 IN NS be.dns.eu.
eu. 172800 IN NS si.dns.eu.
;; Received 341 bytes from 199.9.14.201#53(199.9.14.201) in 69 ms
europa.eu. 86400 IN NS ns3bru.europa.eu.
europa.eu. 86400 IN NS ns4az1.europa.eu.
europa.eu. 86400 IN NS ns2lux.europa.eu.
europa.eu. 86400 IN NS ns1.bt.net.
europa.eu. 86400 IN NS ns1lux.europa.eu.
europa.eu. 86400 IN NS ns2eu.bt.net.
europa.eu. 86400 IN NS ns2bru.europa.eu.
europa.eu. 86400 IN NS ns1bru.europa.eu.
europa.eu. 86400 IN NS ns3lux.europa.eu.
;; Received 431 bytes from 185.151.141.1#53(185.151.141.1) in 115 ms
ecb.europa.eu. 3600 IN NS pdns109.ultradns.net.
ecb.europa.eu. 3600 IN NS pdns109.ultradns.org.
ecb.europa.eu. 3600 IN NS ns1.coltnet.at.
ecb.europa.eu. 3600 IN NS pdns109.ultradns.biz.
ecb.europa.eu. 3600 IN NS pdns109.ultradns.com.
ecb.europa.eu. 3600 IN NS ns8.colt.net.
;; Received 222 bytes from 147.67.12.3#53(147.67.12.3) in 126 ms
www.ecb.europa.eu. 300 IN CNAME www-ecb-europa-eu.ax4z.com.
;; Received 75 bytes from 156.154.65.109#53(156.154.65.109) in 9 ms
real 0m0.461s
user 0m0.008s
sys 0m0.010s
$
the second time , when this query is cached i get :
$ time dig +trace www.ecb.europa.eu
; <<>> DiG 9.8.1 <<>> +trace www.ecb.europa.eu
;; global options: +cmd
. 5382 IN NS j.root-servers.net.
----//----
www.ecb.europa.eu. 300 IN CNAME www-ecb-europa-eu.ax4z.com.
;; Received 75 bytes from 156.154.65.109#53(156.154.65.109) in 9 ms
real 0m0.104s
user 0m0.006s
sys 0m0.007s
$ dig -v
DiG 9.8.1
$
My dig version as you see doesn't query RRSIG, NSEC records. On the
same network a ubuntu 20.04 machine takes indeed much longer :
ubuntu at ubuntu:~$ time dig +trace www.ecb.europa.eu
; <<>> DiG 9.16.1-Ubuntu <<>> +trace www.ecb.europa.eu
;; global options: +cmd
. 5812 IN NS a.root-servers.net.
. 5812 IN NS c.root-servers.net.
. 5812 IN NS m.root-servers.net.
. 5812 IN NS k.root-servers.net.
. 5812 IN NS g.root-servers.net.
--//--
;; Received 891 bytes from 147.67.12.3#53(ns2lux.europa.eu) in 16 ms
www.ecb.europa.eu. 300 IN CNAME www-ecb-europa-eu.ax4z.com.
;; Received 86 bytes from 2001:502:4612::91#53(pdns109.ultradns.org) in 4 ms
real 0m3.052s
user 0m0.021s
sys 0m0.020s
ubuntu at ubuntu:~$ dig -v
DiG 9.16.1-Ubuntu
ubuntu at ubuntu:~$
--
Robert M. Stockmann - RHCE
Network Engineer - UNIX/Linux Specialist
crashrecovery.org stock at stokkie.net
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