EE Wi-Fi Calling does not initiate on specific networks (no DNS / no IPSec)

[Thomaschui]

Post content

Hi EE,

I’m trying to understand a Wi-Fi Calling behaviour specific to EE, which appears to be location / public-IP dependent, rather than a handset or Wi-Fi issue.

Summary

On certain Wi-Fi networks, EE Wi-Fi Calling does not initiate at all:

• No DNS queries

• No UDP 500 (IKE)

• No UDP 4500 (IPSec NAT-T)

This has been verified with packet capture (Wireshark) on both iOS and Android.

The same Wi-Fi network successfully supports Wi-Fi Calling for O2, Vodafone and Three.

Test results

Locations

• ✅ Reading – EE Wi-Fi Calling works normally

• ❌ Newbury – EE Wi-Fi Calling never initiates

• ❌ Bristol – same behaviour as Newbury

Behaviour in Newbury / Bristol

• Airplane mode + Wi-Fi: waited 60+ seconds, no Wi-Fi Calling

• Attempting to place a call: no Wi-Fi Calling

• Packet capture shows:

  • No DNS queries

  • No IPSec attempt

• IPv4 only

• DNS tested:

  • BT DNS

  • Google (8.8.8.8)

  • Cloudflare (1.1.1.1)
    → No difference

• No captive portal

Controls

• Same Wi-Fi, same devices:

  • O2 / Vodafone / Three can all establish Wi-Fi Calling

  • Works both in airplane mode and normal mode

• EE SIM works fine:

  • At home

  • In Reading

• Reading and Newbury have identical local network configuration, only the public IP differs

Devices

• EE consumer SIM

• iOS 26.1

• Android (same result)

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Conclusion

This does not appear to be:

• a Wi-Fi issue

• a DNS issue

• a handset or OS issue

It looks like EE Wi-Fi Calling is being prevented from initiating by an internal pre-check / policy decision, likely based on public IP / routing / location, as the client does not even start the DNS or IPSec phase.

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Question

Can this be reviewed or escalated to the EE network / IMS / Wi-Fi Calling team to confirm whether this behaviour is expected or configurable?

I’m happy to provide further technical details if needed.

Thanks.

[XRaySpeX]

Who is the BB provider in the 3 locations? Using which router?

[Thomaschui]

All locations are using BT 500 Mbps leased lines, and the router in use is a TP-Link ER8411.

The key point is that the same router model, firmware and configuration is used in Reading and Newbury.

• Reading: EE Wi-Fi Calling works normally
• Newbury / Bristol: EE Wi-Fi Calling does not initiate at all

The only difference between these sites is the public IP / routing provided by the BT leased line, not the local router, firewall or Wi-Fi configuration.

On the same ER8411 router and Wi-Fi network, Wi-Fi Calling works immediately with O2, Vodafone and Three SIMs, both in and out of airplane mode.

Packet capture confirms that in Newbury/Bristol the EE Wi-Fi Calling client does not even begin DNS resolution or IPSec negotiation, which suggests a decision made before Wi-Fi Calling setup, rather than traffic being blocked by the router or ISP.

If EE Wi-Fi Calling has any specific requirements or exclusions related to leased-line IP ranges, routing, MTU, or NAT behaviour, I’m happy to validate those – but based on the identical setup comparison, this appears to be EE-specific behaviour.

[Thomaschui]

Is it possible for this to be escalated to an EE network or IMS engineer who can review the findings and help determine the root cause?

I’m happy to provide packet capture evidence or any additional technical details required.

[Rach_H]

Hi @Thomaschui,

Welcome to the Community!

Im sorry to hear about the trouble you've been having. The best way to get this escalated would be to give our team a call, and the team will be able to look into what is happening with your calls.

Rach

[XRaySpeX]

I can't believe that a phone, designed for nationwide, if not worldwide use, would have diff behaviour, in the same environment, in Reading from the rest of S. England.

[Andy_65]

@XRaySpeX There's been a few similar threads recently, today I'm 15 miles from home and WiFi calling will not show as working for me.  This is on Sky FTTP WiFi, I have no problem at home with EE broadband. Unless something has changed in ios where WiFi calling doesn't show if there's sufficient signal strength (which I doubt), then it would seem to me that something is going on.