Resolving problems with Airtel VoWiFi, WiFi Calling

Disclaimer - this is one possible solution, for a specific scenario. This post does not aim to resolve all possible WiFi Calling issues.
Posting this here for people who have been trying to resolve issues with WiFi calling not working on Airtel, it took me a really long while to figure this out.

Problem: Handset is configured correctly for WiFi Calling, have Airtel v-fiber/Xstream broadband at home. Handset does not show the VoWiFi icon at home, but shows the icon when I visit a friend. ViWiFi does not work over my own Airtel home broadband, but works with someone else's Airtel broadband.
Solution TL;DR: Check router DNS settings

Details:
VoWiFi was launched and I was could enable the settiing on my iPhone 7, however the VoWiFi indication (network name changes to AirTel WiFi on an iPhone) never showed up on my mobile handset. In the interim, i visited a friend who has AirTel broadband too, and on connecting to his home internet, VoWiFi showed up as active. Did my research online, found that my home router might not be allowing traffic on UDP ports 4500 and port 500. Experimented with my router, set up port forwarding rules, and still couldnt get WiFi calling to work. Called Airtel moble customer care and Airtel broadband customer care, got passed from department to department with no luck, spent several minutes on multiple occasions with customer care and got fed up. Was told by customer care executives that there is no option on their CRM software to register complaints for WiFi calling, they remotely checked my router and found everything to be set up correctly too.

The Solution:
Randomly while browsing forums where people reported such issues with T-Mobile and Verizon, I chanced upon a post which set my head ticking. I remember having changed the DNS servers configured on the home router a few years ago. I had changed the primary and secondary DNS servers from the default Airtel provided DNS server addresses to Google DNS (8.8.8.8, 8.8.4.4). I called up customer care, got Airtel's primary and secondary DNS server addresses for vFiber in New Delhi (202.56.215.54, 202.56.215.55) restarted my router, disabled and re-enabled Wifi calling on my mobile phone and restarted that too for good measure..
.... and voila VoWiFi!!

I guess for this particular scenario, the issue would be automatically resolved when Airtel opens up WiFi calling to other ISPs because apparently as of now in my area only their own DNS servers are able to look up the Wifi Calling servers. Hope this post helps someone else too.
 
Did you try setting up your phone cell network to 3g instead of LTE?

Once i did that vowifi became 100% stable. Once i step outside the house i change back to LTE.
For me it was working fine till now but, then suddenly i stop seeing the WiFi icon whereas at the same time it was working fine on my android phone connected to same wifi and using airtel sim. I use airtel postpaid sim and BSNL FTTH broadband on iPhone 8. I tried changing the DNS server but that did not work for me. Then, i just switched my mobile network from 3g to LTE and then again to 3g now i can see the WiFi icon on top.
Ps: I see different solutions worked for different people. And, I am on Airtel ₹899 postpaid plan.
 
Has anyone managed to get VoWifi to work on Jio, Airtel or Vi when being outside India?
 
Working settings as on 26 Jan 2022 (changes made in bold):

1. Network > Wan >
Primary DNS: 117.96.122.81
Second DNS: 202.56.215.54
Service: VOIP [no], TR-069 [yes], INTERNET [yes], IPTV [no]

2. Security > Firewall >
Security Level: Off
Attack Protection: Enable

3. Security > DMZ and ALG (in some routers Security > ALG) > IPSEC [yes]

4. Application > UPnP / DLNA > Enable UPnP / DLNA [no]

5. Network > DNS > DNS Proxy Enabled [yes] > OK to reboot

6. Reboot the router if not prompted on #5 above.

Before these changes, I would never see "Airtel Wifi" on the phone, or get Voice over Wifi (VoWiFi) working (it would appear briefly after rebooting the router but disappear in few minutes). But after the above changes, it seems to be consistently working for last 1 hour.

I believe it is either the primary DNS server change or enabling IPSEC that did the trick (don't have the patience to check exactly which one).

Hope this helps.
 
IPSEC is only require for vowifi as it uses port 4500.
ideally all routers with default settings work properly. If you tweak, do remember to enable all ALG in router settings.
Regarding DNS, all Indian DNS would support vowifi in India.
 
Airtel vowifi is not working on airtel n/w both on airtel broadband and (fixed after router reboot) on Hotspot connected to airtel 4g. It is working fine with Hotspot connected to vi 4g
 
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I am using NextDNS and have configured so that my phone can be identified in the DNS logs. What I have noticed is, the DNS call for VoWifi bypasses the private DNS and the request is directly handled by the router.
 


I am using Airtel Postpaid wifi in iPhone 14 with Airtel FIber Nokia Modem.
Many times I do not hear voice of other person but on turning off wifi I am able to hear. Sometimes modem reboot do help.

Same problem is being faced on S22.
 
IF YOU ARE USING ZTE ROUTER (AIRTEL BROADBAND)
LOGIN TO YOUR ROUTER

THEN GO TO "INTERNET" TAB
THEN "SECURITY"
THEN "ALG" TAB
TURN ON ALL "ALG".

IT WILL START WORKING.
 
I am experiencing an issue with call dropping on Airtel 4G. Earlier the calls would drop as the network coverage is bad here, but after I got a phone with VoWiFi, the issue was fixed for a few months, but now the calls are dropping again, when I see the network status, there's no Airtel WiFi, I have to turn airplane mode on and off to get it to work again, and WiFi calling still gets disabled on its own in a brief while. Experiencing this issue on iOS.
 
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Airtel WiFi was being displayed and the moment I got a call within a few seconds it got turned off. Is there any solution for this?
 
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