Issues with *.svc.ms resolving

[Matthew Sutton]

Google DNS has been having issues resolving *.svs.ms domains associated with office 365.

4-northcentralus1-pushp.svc.ms 

4-northcentralus1-pushp.svc.ms

6-northcentralus1-pushp.svc.ms 

 6-northcentralus1-pushp.svc.ms 

 4-westeurope1-pushp.svc.ms 

 4-westeurope1-pushp.svc.ms

When I use google DNS to resolve I get CNAME records back and no A record.  When I use quad9 to resolve I get CNAME and A record back.

# dig 4-northcentralus1-pushp.svc.ms @8.8.8.8

; <<>> DiG 9.16.15 <<>> 4-northcentralus1-pushp.svc.ms @8.8.8.8

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 24989

;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 512

;; QUESTION SECTION:

;4-northcentralus1-pushp.svc.ms.        IN      A

;; ANSWER SECTION:

4-northcentralus1-pushp.svc.ms. 1796 IN CNAME   4-northcentralus1.pushp.svc.ms.b-0013.b-msedge.net.

4-northcentralus1.pushp.svc.ms.b-0013.b-msedge.net. 239 IN CNAME 4-northcentralus1.pushp.svc.ms.

4-northcentralus1.pushp.svc.ms. 1796 IN CNAME   srv.4.northcentralus1-pushp.cloudapp.net.

;; AUTHORITY SECTION:

cloudapp.net.           59      IN      SOA     prd1.azuredns-cloud.net. msnhst.microsoft.com. 2107898940 900 300 604800 60

;; Query time: 60 msec

;; SERVER: 8.8.8.8#53(8.8.8.8)

;; WHEN: Mon Jul 12 11:21:26 CDT 2021

;; MSG SIZE  rcvd: 288

And then using quad 9

# dig 4-northcentralus1-pushp.svc.ms @9.9.9.9

; <<>> DiG 9.16.15 <<>> 4-northcentralus1-pushp.svc.ms @9.9.9.9

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4878

;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 1232

;; QUESTION SECTION:

;4-northcentralus1-pushp.svc.ms.        IN      A

;; ANSWER SECTION:

4-northcentralus1-pushp.svc.ms. 3600 IN CNAME   4-northcentralus1.pushp.svc.ms.b-0013.b-msedge.net.

4-northcentralus1.pushp.svc.ms.b-0013.b-msedge.net. 240 IN CNAME b-0013.b-msedge.net.

b-0013.b-msedge.net.    181     IN      A       13.107.6.168

;; Query time: 128 msec

;; SERVER: 9.9.9.9#53(9.9.9.9)

;; WHEN: Mon Jul 12 11:21:56 CDT 2021

;; MSG SIZE  rcvd: 153

[Tianhao Chi]

Hi Mathew,

I've looked at the problem and found out the authoritative nameserver is giving inconsistent results. ns1.b-msedge.net. and ns2.b-msedge.net. sometime gives b-0013.b-msedge.net. (valid result) and sometimes 4-northcentralus1.pushp.svc.ms. (NXDOMAIN in the end) for 4-northcentralus1.pushp.svc.ms.b-0013.b-msedge.net. I am also seeing the same resolving issue with 1.1.1.1 or 9.9.9.9. They also gives NXDOMAIN occasionally. Please contact the authoritative nameserver's operator on fixing this problem.

$ for _ in {1..20}; do dig +short @ns1.b-msedge.net. 4-northcentralus1.pushp.svc.ms.b-0013.b-msedge.net. CNAME; done

b-0013.b-msedge.net.

4-northcentralus1.pushp.svc.ms.

4-northcentralus1.pushp.svc.ms.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

4-northcentralus1.pushp.svc.ms.

b-0013.b-msedge.net.

4-northcentralus1.pushp.svc.ms.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

b-0013.b-msedge.net.

[Matthew Sutton]

Thanks, I will reach out to them.