Singtel Wifi calling

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xiaofan

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A7997A said:
It is actually a scrolling "Wi-Fi Calling", if you don't see that, it is not working.
Not sure what you meant by "I can see extra device listed if I also enable the option to allow WiFi calling on other devices."
Click to expand...

1) Thanks. So it is not working here -- tested yesterday using my wife's iPhone 14 fully updated.

2) I mean the following. I can see her old iPhone 7+ listed (ON at the time).

Her old iPhone X (OFF at the time) was not listed.

https://support.apple.com/en-sg/108066

Add a device to use it with Wi-Fi calling​

  1. Check that the device you want to add has the latest version of software.
  2. On your iPhone, go to Settings > Mobile Service. If your iPhone has multiple SIMs, choose a line (below SIMs).
  3. Tap Wi-Fi Calling and turn on Wi-Fi Calling on This iPhone.
  4. Go back to the previous screen, then tap Calls on Other Devices.
  5. Turn on Allow Calls on Other Devices if it's not on. A list of your eligible devices will appear under Allow Calls On.
  6. Turn on each device that you want to use with Wi-Fi Calling.
 
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froztheart

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A7997A said:
Don't happen to be using original iOS right ?
Factory reset ?
Click to expand...
Whatchu mean Original IOS? Like IOS 18 instead of the latest IOS 26?
If you're talking about the version, then both 13PM & newer 16PM (updated to IOS 26) all don't get VoWFI across ST/SH/M1. :s13:

Nah, not going for factory reset just for this yet, but might do it as a last resort.

A7997A said:
It is actually a scrolling "Wi-Fi Calling", if you don't see that, it is not working.
Not sure what you meant by "I can see extra device listed if I also enable the option to allow WiFi calling on other devices."
Click to expand...
Yup, the " ST/SH/M1 WIFI Calling" will be scrolling in the control centre/status bar if it's working.
Not there means not working which is what I am facing.


loganrunning said:
yeah, i can't think of any other reason, other than correct profile not loaded at telco backend.

time to talk/email their customer service
Click to expand...
Yup, trying to ascertain it's not user issue before bringing up to telco to troubleshoot.
 
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A7997A

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froztheart said:
Whatchu mean Original IOS? Like IOS 18 instead of the latest IOS 26?
If you're talking about the version, then both 13PM & newer 16PM (updated to IOS 26) all don't get VoWFI across ST/SH/M1. :s13:
Click to expand...
Referring to the very original iOS like iOS 15 for the 13, just to rule out this possibility.
How about those iPhones on other wifi networks ? Esp one that has known iPhone working. Does wifi calling work on those networks ?
If it works on other network, it has to be something with your home network.
If it doesn't, might be something on the phone.
 
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GlassDoor

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A7997A said:
Referring to the very original iOS like iOS 15 for the 13, just to rule out this possibility.
How about those iPhones on other wifi networks ? Esp one that has known iPhone working. Does wifi calling work on those networks ?
If it works on other network, it has to be something with your home network.
If it doesn't, might be something on the phone.
Click to expand...
technically.. not possible for enduser to restore old iphone firmware. apple stops signing older iOS firmware once you are on the new one.
 
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GlassDoor

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A7997A said:
True, but can one possible don't upgrade all these years ?
Click to expand...
of course but thats beside the point.

for the sake of discussion.
I have a old iphone 7 from HK (uses qualcomm modem, sg iphone 7 uses intel modem) and I use it as a backup phone exclusively on airplane mode and is on wifi calling 100% of the time. no issues.
over the last few years, I have use iphone X, (from US) iphone 12PM(from HK). all no issues with singtel wifi calling. YMMV
 
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A7997A

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GlassDoor said:
of course but thats beside the point.

for the sake of discussion.
I have a old iphone 7 from HK (uses qualcomm modem, sg iphone 7 uses intel modem) and I use it as a backup phone exclusively on airplane mode and is on wifi calling 100% of the time. no issues.
over the last few years, I have use iphone X, (from US) iphone 12PM(from HK). all no issues with singtel wifi calling. YMMV
Click to expand...
I also use a XR for wifi calling almost full time starting from iOS 14 until iOS 18, all of which works.
But this is an area to rule out as there are related update over the years, esp since froztheart's issue seems rather strange.
 
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xiaofan

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Since I am using OpenWRT router, the first thing I look at is the Firewall settings. It has already the Firewall rules required to enable VoWiFi by defy. And my Android phone (Poco X7 Pro) has no issues with VoWiFi using the same Singtel S$15.28 SIM Only plan as my wife's iPhone 14.

So this rules out home networking firewall issue.

Bash: 
root@openwrt18:~# cat /etc/config/firewall

config defaults
        option input 'REJECT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option synflood_protect '1'
       
config defaults
        option input 'REJECT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option synflood_protect '1'

config zone 'lan'
        option name 'lan'
        option network 'lan wg_lan'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'ACCEPT'

config zone 'wan'
        option name 'wan'
        list network 'wan'
        list network 'wan6'
        option input 'REJECT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option masq '1'
        option mtu_fix '1'

config forwarding
        option src 'lan'
        option dest 'wan'
...
...
config rule
        option name 'Allow-IPSec-ESP'
        option src 'wan'
        option dest 'lan'
        option proto 'esp'
        option target 'ACCEPT'

config rule
        option name 'Allow-ISAKMP'
        option src 'wan'
        option dest 'lan'
        option dest_port '500'
        option proto 'udp'
        option target 'ACCEPT'
...
 
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froztheart

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A7997A said:
Referring to the very original iOS like iOS 15 for the 13, just to rule out this possibility.
How about those iPhones on other wifi networks ? Esp one that has known iPhone working. Does wifi calling work on those networks ?
If it works on other network, it has to be something with your home network.
If it doesn't, might be something on the phone.
Click to expand...
A7997A said:
True, but can one possible don't upgrade all these years ?
Click to expand...
No la, how to live with such an outdated IOS. Apps not going to be supported and forced to update one.
Don't see any benefits to stay on older IOS too. :s13:

My MY SIM card has VoWIFI as compared to my SG SIM card so don't seem to be a "network" issue at least?

GlassDoor said:
of course but thats beside the point.

for the sake of discussion.
I have a old iphone 7 from HK (uses qualcomm modem, sg iphone 7 uses intel modem) and I use it as a backup phone exclusively on airplane mode and is on wifi calling 100% of the time. no issues.
over the last few years, I have use iphone X, (from US) iphone 12PM(from HK). all no issues with singtel wifi calling. YMMV
Click to expand...
A7997A said:
I also use a XR for wifi calling almost full time starting from iOS 14 until iOS 18, all of which works.
But this is an area to rule out as there are related update over the years, esp since froztheart's issue seems rather strange.
Click to expand...
So to speak, both of you are using IOS though "older" models are their VoWIFI are all working on your ST/SH/M1 SIM cards?
Not I'm thinking whether my iCloud account is causing any issues instead... since network & IOS don't seem to be the root cause...
 
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A7997A

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froztheart said:
My MY SIM card has VoWIFI as compared to my SG SIM card so don't seem to be a "network" issue at least?
Click to expand...
Still possible, but low likelyhood.
Testing your phone on a wifi network known to support wifi calling for iPhone would be a more conclusive test.
froztheart said:
So to speak, both of you are using IOS though "older" models are their VoWIFI are all working on your ST/SH/M1 SIM cards?
Click to expand...
Maxx & eight works on XR iOS 18 & iPhone 14 iOS 26.
I don't have ST MNO sims, and ST MVNO doesn't support VoWifi.
 
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GlassDoor

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xiaofan said:
Since I am using OpenWRT router, the first thing I look at is the Firewall settings. It has already the Firewall rules required to enable VoWiFi by defy. And my Android phone (Poco X7 Pro) has no issues with VoWiFi using the same Singtel S$15.28 SIM Only plan as my wife's iPhone 14.

So this rules out home networking firewall issue.

Bash: 
root@openwrt18:~# cat /etc/config/firewall

config defaults
        option input 'REJECT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option synflood_protect '1'
    
config defaults
        option input 'REJECT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option synflood_protect '1'

config zone 'lan'
        option name 'lan'
        option network 'lan wg_lan'
        option input 'ACCEPT'
        option output 'ACCEPT'
        option forward 'ACCEPT'

config zone 'wan'
        option name 'wan'
        list network 'wan'
        list network 'wan6'
        option input 'REJECT'
        option output 'ACCEPT'
        option forward 'REJECT'
        option masq '1'
        option mtu_fix '1'

config forwarding
        option src 'lan'
        option dest 'wan'
...
...
config rule
        option name 'Allow-IPSec-ESP'
        option src 'wan'
        option dest 'lan'
        option proto 'esp'
        option target 'ACCEPT'

config rule
        option name 'Allow-ISAKMP'
        option src 'wan'
        option dest 'lan'
        option dest_port '500'
        option proto 'udp'
        option target 'ACCEPT'
...
Click to expand...

both are incoming rules. Not relevant.
No routers by default will block outgoing ikev2 traffic. So I will look elsewhere.

to "force" wifi calling, go into airplane mode with wifi still enabled. (also toggle (disble then enable again)the wifi calling option on the iphone to be sure)

personally, in the past my headaches with wifi calling had been related to DNS. So if you want to be absolutely sure. for testing switch dns providers to either 1.1.1.1 or 8.8.8.8 directly with no middle man/filtering in between. If you use openwrt, by default dnsmasq will be used as a forwarder dns middle man. On the wifi setting on the iphone, set dns to 1.1.1.1 or 8.8.8.8 directly and not the router's ip
 
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A7997A

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GlassDoor said:
both are incoming rules. Not relevant.
No routers by default will block outgoing ikev2 traffic. So I will look elsewhere.

to "force" wifi calling, go into airplane mode with wifi still enabled. (also toggle (disble then enable again)the wifi calling option on the iphone to be sure)

personally, in the past my headaches with wifi calling had been related to DNS. So if you want to be absolutely sure. for testing switch dns providers to either 1.1.1.1 or 8.8.8.8 directly with no middle man/filtering in between. If you use openwrt, by default dnsmasq will be used as a forwarder dns middle man. On the wifi setting on the iphone, set dns to 1.1.1.1 or 8.8.8.8 directly and not the router's ip
Click to expand...
Unless using a firewall without a default allow all outgoing rule, but someone doing that would usually knows that he needs to allow everything specifically.

Restarting wifi calling can certainly be useful, more so on Android phones, but I think still something to try on iPhones. Restarting wifi on the phone can fix issue some times, so try that as well. Also note that in some case wifi calling can take up a couple of minutes to appear, though it typically happens within 10-15 seconds.

DNS can certainly be a problem. Wifi calling need to resolve the mobile gateway FQDN (for Singtel it is
epdg.epc.mnc001.mcc525.pub.3gppnetwork.org), so if there is an issue with this process, wifi calling wouldn't work. For Singtel, check for traffic to and fro 111.65.100.1 & 111.65.100.17.
 
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froztheart

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A7997A said:
Still possible, but low likelyhood.
Testing your phone on a wifi network known to support wifi calling for iPhone would be a more conclusive test.

Maxx & eight works on XR iOS 18 & iPhone 14 iOS 26.
I don't have ST MNO sims, and ST MVNO doesn't support VoWifi.
Click to expand...
Yeah, literally is what I shared, on the network that shows VoWIFI on my MY SIM card the SG SIM card doesn't reflect VoWIFI weirdly.
So can say that network issue is pretty much "eliminated", no?
GlassDoor said:
if it were me... this is the test i will do before going further.
Click to expand...
Both networks at home, has the same results too.
MY SIM card on network 1 - VoWIFI reflect. (13PM + 16PM)
MY SIM card on network 2 - VoWIFI reflect. (13PM + 16PM)

SG SIM card on network 1 - No VoWIFI (13PM + 16PM)
SG SIM card on network 2 - No VoWIFI (13PM + 16PM)

IOS versions 18 on 13PM & 26 on 16PM for the observation conducted above.

Which brings me to a logical conclusion that there's just something affecting specifically SG SIM cards on my iPhones.
But no idea what it seem to be since "network" seems to be fine? IOS don't seem to possibly be the issue too.
 
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A7997A

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froztheart said:
Yeah, literally is what I shared, on the network that shows VoWIFI on my MY SIM card the SG SIM card doesn't reflect VoWIFI weirdly.
So can say that network issue is pretty much "eliminated", no?

Both networks at home, has the same results too.
MY SIM card on network 1 - VoWIFI reflect. (13PM + 16PM)
MY SIM card on network 2 - VoWIFI reflect. (13PM + 16PM)

SG SIM card on network 1 - No VoWIFI (13PM + 16PM)
SG SIM card on network 2 - No VoWIFI (13PM + 16PM)

IOS versions 18 on 13PM & 26 on 16PM for the observation conducted above.

Which brings me to a logical conclusion that there's just something affecting specifically SG SIM cards on my iPhones.
But no idea what it seem to be since "network" seems to be fine? IOS don't seem to possibly be the issue too.
Click to expand...
The whole point of us asking you to test on another network is to confirm that your iphone works for SG sims for vowifi. None of your test proves that.

This is useful since you are not able to conclusively determine if there is an issue with your network.
 
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xiaofan

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Looks like my issue may be different.

If I change the phone to airplane mode and then connect to WiFi, it seems to me VoWiFi is not working. However, I can see "SingTel WiFi Calling" briefly displayed and then disappear in Control Centre once I enable back mobile data.

And I was wrong, the phone has not yet upgraded to iOS 26. I will update the phone and check again.
 
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xiaofan

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After rebooting the iPhone 14, Singtel WiFi calling is working. Tested by switching to airplane mode and then connecting to WiFi, then calling different numbers (SingTel, M1 Maxx and Eight).

Still on iOS 18.7.2.

I will upgrade the phone to iOS 26.1 and then check again.
 
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A7997A

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xiaofan said:
After rebooting the iPhone 14, Singtel WiFi calling is working. Tested by switching to airplane mode and then connecting to WiFi, then calling different numbers (SingTel, M1 Maxx and Eight).

Still on iOS 18.7.2.

I will upgrade the phone to iOS 26.1 and then check again.
Click to expand...
Looks like a bug or something stuck then. Sounds like it could be something for froztheart to try ?
 
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xiaofan

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xiaofan said:
After rebooting the iPhone 14, Singtel WiFi calling is working. Tested by switching to airplane mode and then connecting to WiFi, then calling different numbers (SingTel, M1 Maxx and Eight).

Still on iOS 18.7.2.

I will upgrade the phone to iOS 26.1 and then check again.
Click to expand...

Just upgraded the iPhone 14 to iOS 26.1 and no issues with Singtel WiFi Calling.
 
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