I've been seeing an issue on a couple iOS devices when they are connected to my home network. My home network has IPv6 enabled.
With IPv6 enabled after a certain period of time, I no longer receive calls. My phone still shows that wifi calling is on. I can make calls during that time. When I disable IPv6 the issue disappears and I am able to receive calls all the time.
When I was troubleshooting the issue, it seem to be related to how VZW does Wifi calling. On IPv4 networks, calls connect over IPSec via NAT-T, where traffic is initiated from the device and return traffic from VZW is allowed. The ESP packets that contain the call are forwarded back to the device that has the port open for the IKEv2 keepalives (4500/udp).
With IPv6, the IKEv2 traffic occurs on port 500/udp, but the call traffic is standard ESP protocol 50 traffic, not 500/udp. This causes most firewalls to drop the traffic due because the traffic isn't started from the LAN side. When I create a firewall rule to allow ESP traffic inbound from wo.vzwwo.com, inbound calls immediately start to work.
I don't know if this is an issue on VZW's side or iOS but it seems to have only started to occur in the last two to three months. I am happy to discuss further with VZW engineering.
We are residential integrators and provide network/wifi coverage for homes that normally require a multitude of waps to cover the home. Using a fios router to our PoE switch and out to the waps has always provided this well. It always has, but in the past few months is when we have began to get complaints from customers about their wifi calls dropping. Speeds are fantastic through the home (at gigabit incoming, our wireless can achieve 580Mbps +). This is mostly anywhere in and outside of the home. I would love to see something relative to wifi calling protocols built into the fios routers where we can make changes because when it doesn't work and starts to drop calls, we have no recourse. We can always add a 3rd party vpn router to allow us these features, but if the customer has a MoCa cable box system, this isn't really an option. Any other thoughts on wifi calling using a Fios cr1000 or g3100 router ? I'd be interested in other experiences. This seems a topic not much discussed specifically.
Thank you! I did just discover that if I turn airplane mode on and then go to settings and toggle wifi calling off and back on. That corrects the issue! It seems to me they have a bug in their coding. I say this like I know what I am talking about, but I don’t! Lol But, maybe the work around I found would be helpful to the Verizon engineers to compare what is happening before my work around and after the work around.
I think the issue lies within cell broadcast range and wifi signal strength more-so than protocol at this point. If the wifi signal is great and your phone is active "wifi calling", but happens to see a trickle of a cell broadcast, it will try to connect to that signal and then drop the call. If the device is in airplane mode, normally this will prove wifi calling is working as it should since it cannot see any cellular broadcasts due to it being in "airplane mode"'.
It seems if a cell signal that is coming into the home is powerful enough to force the device to connect to that instead of the "wifi calling" feature - and thats when the call most likely drops. If the device is working and not dropping calls in "airplane mode", then this proves true. If it is still dropping calls while in airplane mode, then this will point to the provider or lack of wifi broadcast range.
I also want to confirm that the issue *never* occurs when airplane mode is enabled, which further supports your position on the underlying cause.
I have experienced the exact same issue and know other Verizon customers who have also experienced it. Has Verizon acknowledged the issue or provided any response? @l116991 did you leave ipv6 disabled as a temporary workaround?
I have done that. ipv6 disabled, no luck with that helping.
I had a Verizon support manager talking to me about the issue but they seemed to have moved on.
I’ve left IPv6 disabled at home and have no issues with WiFi calling. Frustrating because VZW could have a keep alive or something similar flow through the IPSec tunnel and it would be fine. The program assumes all gateways/firewalls are keeping track of the tunnels.
I've opened a case and Verizon Engineering is investigating. I shared the details you provided above, which pretty clearly identifies the issue with the Verizon router. Let's see what they come back with.
I've temporarily disabled IPv6 and haven't experienced the issue since but as mentioned, that is only a temporary workaround.
Hi there Sanchezam! We want to make sure that you are receiving exceptional service. Your device uses IKEv2 with EAP-AKA authentication with Verizon network, leveraging the subscriber data and security credentials stored in the SIM card. If you are still having issues, please indicate and we can troubleshoot individually with you.
-Erica
Hello. This is not related to the issue many of us are having. I've opened a case and it is being investigated. I'm hopeful Verizon will be able to identify a solution.
Update. Verizon transferred the ticket to Verizon Wireless. From what I can see, I don't believe Verizon Engineering examined the issue closely since it is clearly a problem with the router configuration.
I'm disappointed it was transferred, but we'll see how Verizon Wireless responds. Verizon has offered me an extender, which I've declined, since I would like to see the problem resolved for myself and all other impacted customers.
Hi there Sanchezam, we're disappointed to hear the ticket hasn't been resolved but transferred to another department. We'd be more than happy to help by providing you with an update on your ticket, and continuing any troubleshooting to assist with resolving this concern. Keep an eye out for a private note, so we can provide you with further assistance.
~Brian
Hello. I believe I am also having this issue as well. Calls were being sent to voicemail automatically and seemed to be isolated to when WiFi calling is activated. My wife’s iPhone is not having this issue. It is isolated to my line. I worked with the Verizon network team and they seemed to isolate the issue to WiFi calling as well when they traced the calls. I currently disabled ipv6 as well on my g3100 router but it seems more of a workaround that an actual fix. Has there been any further look into this by engineering or support?
@calvotj Verizon Wireless confirmed it's an issue with the FIOS router (which we knew) and the ticket has been transferred back the FIOS team. I spoke to the case handler and asked that FIOS Engineering take a closer look at this issue and reiterated that we are happy to assist them if that would be helpful in finally resolving this issue.
@Sanchezam Thanks for the update. I agree it is definitely an issue with the router denying the incoming WiFi calling traffic.
When I was working with the wireless network team it seemed to be good for a days and then it would start sending calls to voicemail. If I disconnected and reconnected WiFi it start the cycle again.
What is really odd is only my iPhone (16 pro) is affected, my wife’s has no issues. (14 pro max)
If engineering needs any logs or anything let me know I’d be happy to help.
I am having same issue. Extender didn’t help at all, if WiFi calling is turned on.
We never want our customers to be without the ability to make or receive calls. We will send you a private message so we can troubleshoot your connection.
-Toni
Hello. I believe I am also having this issue as well. Calls were being sent to voicemail automatically and seemed to be isolated to when WiFi calling is activated. My wife’s iPhone is not having this issue. It is isolated to my line. I worked with the Verizon network team and they seemed to isolate the issue to WiFi calling as well when they traced the calls. I currently disabled ipv6 as well on my g3100 router but it seems more of a workaround that an actual fix. Has there been any further look into this by engineering or support?
Update: Verizon Wireless confirmed it's an issue with the FIOS router (which we knew) and the ticket has been transferred back the FIOS team. I spoke to the case handler and asked that FIOS Engineering take a closer look at this issue and reiterated that we are happy to assist them if that would be helpful in finally resolving this issue.
I'm having the same issue (started a month or so ago), with a few add-ons.....
1) No calls come in. They go straight to VM with no indication of the call or the VM on my end.
2) No messages come through. If I discover this and restart my phone, messages come flooding in after.
3) All 3 phones in my home (all iphones) are having the same issue.
4) This is ONLY a problem at my home.
5) Restarting daily (in the morning) seems to have "solved" the problem.
Start a new topic or ask questions in the open forum.
