dns oddity with cns7.bluewin.ch - swinog

19 Jun 2013


      Hello list
Does anybody know why cns7.bluewin.ch does answer one out of four specific queries 
with an mixed case DNS answer?
;; QUESTION SECTION:
;_autodiscover._tcp.id.ethz.ch. IN      SRV
;; ANSWER SECTION:
_autodiscover._tcp.id.ethz.ch. 43200 IN SRV     0 100 443 mail.ethz.ch.
;; ANSWER SECTION:
_autodiscover._tcp.id.ethz.ch. 43200 IN SRV     0 100 443 mail.EThZ.CH.
The Outlook mail client is treating the DNS answers case sensitive so mail.ethz.ch and mail.EThZ.CH are not the same.  
Every time the mail client discovers a different "mail.ethz.ch" the user has to accept the new mail.etHz.cH server.
...
From my point of view the use of Bit 0x20 in DNS Labels should happen between caching and authoritative name servers.
http://tools.ietf.org/html/draft-vixie-dnsext-dns0x20-00
Is my point of view wrong?
Regards
Daniel
------------------------------------------------------------------------
Daniel Ambauen
Hostmaster      
ETH Zentrum WET B 1                    mailto:daniel.ambauen@id.ethz.ch
Weinbergstrasse 43                     tel : +41 44 632 35 48
CH-8092 Zürich                         
------------------------------------------------------------------------
C:\dig>dig @195.186.1.162 _autodiscover._tcp.id.ethz.ch srv
; <<>> DiG 9.3.2 <<>> @195.186.1.162 _autodiscover._tcp.id.ethz.ch srv
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 924
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; QUESTION SECTION:
;_autodiscover._tcp.id.ethz.ch. IN      SRV
;; ANSWER SECTION:
_autodiscover._tcp.id.ethz.ch. 43200 IN SRV     0 100 443 mail.ethz.ch.
;; ADDITIONAL SECTION:
mail.ethz.ch.           2775    IN      A       129.132.126.69
;; Query time: 93 msec
;; SERVER: 195.186.1.162#53(195.186.1.162)
;; WHEN: Wed Jun 19 10:50:50 2013
;; MSG SIZE  rcvd: 95
C:\dig>dig @195.186.1.162 _autodiscover._tcp.id.ethz.ch srv
; <<>> DiG 9.3.2 <<>> @195.186.1.162 _autodiscover._tcp.id.ethz.ch srv
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1411
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; QUESTION SECTION:
;_autodiscover._tcp.id.ethz.ch. IN      SRV
;; ANSWER SECTION:
_autodiscover._tcp.id.ethz.ch. 43200 IN SRV     0 100 443 mail.ethz.ch.
;; ADDITIONAL SECTION:
mail.ethz.ch.           2706    IN      A       129.132.126.69
;; Query time: 483 msec
;; SERVER: 195.186.1.162#53(195.186.1.162)
;; WHEN: Wed Jun 19 10:51:04 2013
;; MSG SIZE  rcvd: 95
C:\dig>dig @195.186.1.162 _autodiscover._tcp.id.ethz.ch srv
; <<>> DiG 9.3.2 <<>> @195.186.1.162 _autodiscover._tcp.id.ethz.ch srv
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1611
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; QUESTION SECTION:
;_autodiscover._tcp.id.ethz.ch. IN      SRV
;; ANSWER SECTION:
_autodiscover._tcp.id.ethz.ch. 43193 IN SRV     0 100 443 mail.ethz.ch.
;; ADDITIONAL SECTION:
mail.ethz.ch.           2699    IN      A       129.132.126.69
;; Query time: 156 msec
;; SERVER: 195.186.1.162#53(195.186.1.162)
;; WHEN: Wed Jun 19 10:51:11 2013
;; MSG SIZE  rcvd: 95
C:\dig>dig @195.186.1.162 _autodiscover._tcp.id.ethz.ch srv
; <<>> DiG 9.3.2 <<>> @195.186.1.162 _autodiscover._tcp.id.ethz.ch srv
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1171
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; QUESTION SECTION:
;_autodiscover._tcp.id.ethz.ch. IN      SRV
;; ANSWER SECTION:
_autodiscover._tcp.id.ethz.ch. 43200 IN SRV     0 100 443 mail.EThZ.CH.
;; ADDITIONAL SECTION:
mail.EThZ.CH.           2848    IN      A       129.132.126.69
;; Query time: 202 msec
;; SERVER: 195.186.1.162#53(195.186.1.162)
;; WHEN: Wed Jun 19 10:51:12 2013
;; MSG SIZE  rcvd: 95