I did some digging, so it appears the
DNS name
vowifi.jio.com
resolves differently based on the source IP address of the resolver (or maybe they do make use of the EDNS-Client-Subnet mechanism also, I did not test that).
View attachment 1891
So from India it resolves to
49.44.59.38
&
49.44.59.36
, but from anywhere else it resolves to
49.45.63.2
&
49.45.63.1
. The above image is from OpenDNS cache check (
OpenDNS: Cloud-Delivered Security Enforcement and Intelligence) where you can check how the name resolves from various geographies.
So my guess is, they have this mechanism probably to support VoWiFi during international roaming. When outside India, you get redirected to a different endpoint, and the VoWiFi is enabled only when the required plan or addon is active.
The setup is a bit weird, if I ask
ns1.jio.com
which is one of the nameservers for
jio.com
, it says go ask
ns1/2.vowifi.jio.com
. But they are missing the DNS records for
ns1.vowifi.jio.com
and
ns2.vowifi.jio.com
, but they do send the glue records, so it does work.
Code:
(⎈ |docker-desktop:default)➜ ~ dig vowifi.jio.com @ns1.jio.com.
; <<>> DiG 9.10.6 <<>> vowifi.jio.com @ns1.jio.com.
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3137
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 3
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;vowifi.jio.com. IN A
;; AUTHORITY SECTION:
vowifi.jio.com. 3600 IN NS ns1.vowifi.jio.com.
vowifi.jio.com. 3600 IN NS ns2.vowifi.jio.com.
;; ADDITIONAL SECTION:
ns1.vowifi.jio.com. 3600 IN A 49.44.59.6
ns2.vowifi.jio.com. 3600 IN A 49.44.59.7
;; Query time: 60 msec
;; SERVER: 2405:200:1602:720::4#53(2405:200:1602:720::4)
;; WHEN: Thu May 21 11:15:07 IST 2020
;; MSG SIZE rcvd: 111
But the issue I am facing at times is that
vowifi.jio.com
resolves to the international IP addresses and VoWiFi doesn't work. I do use a caching resolver, so I am trying to pinpoint the actual problem. However, I can definitely say that this isn't set up properly from Jio's perspective.