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Wifi calling seems to be blocked by employers wifi

Adamskiodp

Casual Member
Hi folks,

Not sure where to post this so please feel free to move if needed.

I have WiFi Calling with my giffgaff eSim working fine on my home network (Zen FTTC and the supplied AVN Fritzbox) and also working when using public WiFi in pubs/shops.

For some reason Wifi calling won't work when connected to my employers public WiFi (NHS).

Does anyone know if a network can be setup to block WiFi calling and would it be some kind of obscure security glitch because it's an NHS network and they are extra paranoid about security?

Any ideas gratefully received.
 
Does anyone know if a network can be setup to block WiFi calling and would it be some kind of obscure security glitch because it's an NHS network and they are extra paranoid about security?
My old college had WiFi Calling blocked on the WiFi. I can't remember if it was a port block of just them blocking the 3gpp web address that's used for WiFi Call.

I would ask my dad as he works for the NHS, but he never uses their WiFi given there's a PoW right outside so full 5G on smarty instead.
 
Yes, it's absolutely possible that the WiFi network blocks WiFi calling protocols. It's probably more by accident than intended.

The O2 (and I assume also Giffgaff) WiFi calling seems to be using a traditional VPN protocol based on IKE for its connection, there's some documentation shared about what was needing back in 2019 on the O2 forum

https://community.o2.co.uk/t5/Other-Products-and-Services/Wifi-Calling/td-p/1220417

Whether that is still up to date and whether you can convince the people operating the NHS WiFi to take a look at their config is another question.

I know I heard of this issue a few years ago at one place where the building was particularly effective at blocking mobile signals, and once we permitted the IKE ports we didn't get any more WiFi calling complaints.
 
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Yes, it's absolutely possible that the WiFi network blocks WiFi calling protocols. It's probably more by accident than intended.

The O2 (and I assume also Giffgaff) WiFi calling seems to be using a traditional VPN protocol based on IKE for its connection, there's some documentation shared about what was needing back in 2019 on the O2 forum

https://community.o2.co.uk/t5/Other-Products-and-Services/Wifi-Calling/td-p/1220417

Whether that is still up to date and whether you can convince the people operating the NHS WiFi to take a look at their config is another question.

I know I heard of this issue a few years ago at one place where the building was particularly effective at blocking mobile signals, and once we permitted the IKE ports we didn't get any more WiFi calling complaints.
It could be deliberate. As you mentioned, Wi-Fi calling uses the same ports as IPsec (UDP/500 for IKE and UDP/4500 for NAT-T) so some orgs may choose to block VPN connections on their public wireless networks.

It was the same at my last employer (also public sector). The office building acted as a signal sump and Wi-Fi calling was blocked which meant that every employee was effectively cut off from making or receiving phone calls. After a lot of complaining, they caved and opened up the firewalls.
 
Hi folks,

Not sure where to post this so please feel free to move if needed.

I have WiFi Calling with my giffgaff eSim working fine on my home network (Zen FTTC and the supplied AVN Fritzbox) and also working when using public WiFi in pubs/shops.

For some reason Wifi calling won't work when connected to my employers public WiFi (NHS).

Does anyone know if a network can be setup to block WiFi calling and would it be some kind of obscure security glitch because it's an NHS network and they are extra paranoid about security?

Any ideas gratefully received.
I can confirm that WiFi networks can block WiFi calling (mainly by default or unintent) but if you got the right phone, it will bypass it.

My A13 last year would not work on college WiFi for calling which is a pain because of limited coverage in the area. I believe this might of also applied to the NHS WiFi.

My A54 that I have bought this year have definitely worked for WiFi calling on NHS WiFi and the college WiFi aswell, the only WiFi I know it didn't work was H&M Free WiFi for some reason.

The problem is that no one knows or can tell what is the correct phone to bypass blocked WiFi calling networks, it's just pure luck.
 
I can confirm that WiFi networks can block WiFi calling (mainly by default or unintent) but if you got the right phone, it will bypass it.

My A13 last year would not work on college WiFi for calling which is a pain because of limited coverage in the area. I believe this might of also applied to the NHS WiFi.

My A54 that I have bought this year have definitely worked for WiFi calling on NHS WiFi and the college WiFi aswell, the only WiFi I know it didn't work was H&M Free WiFi for some reason.

The problem is that no one knows or can tell what is the correct phone to bypass blocked WiFi calling networks, it's just pure luck.
I don't quite think this is the case. Especially so given you used two samsungs. They all use the same protocols to connect to WiFi calling (Samsung Frameworks) so there may be something else at play in your case
 
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I don't quite think this is the case. Especially so given you used two samsungs. They all use the same protocols to connect to WiFi calling (Samsung Frameworks) so there may be something else at play in your case
Yeah I just tested it now actually by manually blocking 3gppnetwork.org on Talktalk and my A54 stopped WiFi calling instantly.

So if your WiFi blocks 3gppnetwork.org then it should not work at all. I will try to conenct to an NHS WiFi later to see if I can get WiFi call
 
Will be blocked with it been VPN, I've allowed it access on ours via 3gppnetwork.org for each of the key providers as we have buildings with poor signal.

If you trust has govroam try connecting to that, use your computer login details, that has to allow VPN as part of the requirements to broadcast it.
 
I'm not sure there is a centrally mandated policy for what internet access NHSwifi permits. The landing pages typically foisted on you when you connect are a mixture of local and commercial captive portals, and I am sure there will be some local variation in what has been practically permitted either intentionally or accidentally.

eduroam and govroam do actually specify a minimum set of protocols/ports and that should accessible for a roaming visitor using those services, but even with a written standard you sometimes find that something that should be permitted isn't, but that's more cockup than conspiracy.
 
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My work had blocked Wi-Fi calling, it had also blocked my Eufy doorbell for some reason but I found I could use the 1.1.1.1 free warp VPN and that gave me access to Wi-Fi calling again on the work Wi-Fi.
 
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