WiFi calling outside of cell service range, an impossibility?



What phone do you have? Moto X 2nd Gen
What plan are you on? Republic Refund
Does your plan include data, or just talk & text? Data included

Issue Description

I am a student at a far-off boarding school in the rural US. The only provider servicing the area is US Cellular. This means that while on the campus WiFi I can send texts, but under no circumstances can I complete a phone call. I can receive a call if someone dials my number, but upon answering it, the call fails, never having established a connection.

Undoubtedly this is expected behavior., persisting through both PRL/Profile updates and factory resets. My question is: is there no hope for ever being able to complete calls while outside of cell service? I.e., is this an engineering impossibility? If so, what kind of solutions does the RW team propose for these sorts of cases?


Hi @deborahc.vssqy6,

It sounds like something about your campus Wi-Fi is blocking Wi-Fi calls. My daughter’s high school was a boarding school that was part of the state university system, and the school’s network management team was willing to make adjustments to their network to allow her phone to make and receive Wi-Fi calls. If the network team at your school would be amenable, I’d be glad to help facilitate the same kind of conversation.


Thanks for the reply.

I will reach out to the IT director and ask if they can deploy a fix, and if they need more info I’ll reach out to you.

To clarify, in a perfect world, IT could just open up 6000-29999 UDP to let calls through? Since I can receive calls and voicemail I assume that 5090 UDP and 8883 TCP are open already.


Hi @deborahc.vssqy6,

@jben has a good synopsis of the required ports in his Router Tweaks article, in the Required Ports & Protocol for Open Access section.

What’s important to convey to the IT team is that no ports have to be opened, because the server will not send anything unsolicited. The phone will initiate registration with our VoIP server. It needs to be allowed to transmit to any IP on any port, and maintain the session.

Most network managers understandably do not want to open ports. By allowing trusted devices in the network reach any IP and maintain the session, it’s not necessary to open the ports to unsolicited inbound traffic.


FYI: This specific portion of the document was originally developed with the cooperation of folks from a University IT, a Business/Enterprise IT and Republic Wireless Staff to respond to problems seen by the community users.

  • Republic has recently updated the port used for Voicemail, Messaging SMS/MMS and keep-alive messages to RW servers and provided a major enhancement to the Notification process (when ports are blocked)
  • Router Tweaks is just one of the many user help articles provided by user contributors in Tips & Tricks - Community Forums


Hello @southpaw,

I got a response back from the IT director and he noted in response to,

"​No ports need to be opened of course, since RW servers won’t be sending unsolicited messages “… " ​it needs to be allowed to transmit and maintain a session on 6000-29999 UDP,” that:

“6000-29999 ARE ports. For security, most, if not all, of these ports are closed. This is why your VoIP is not working. I can not open 23,999 ports due to security.”

Is IT misunderstanding the RW requirements here? I linked to the Router Tweaks forum and specifically noted that the ports do not need to be opened. Perhaps there are some more specifics I can point to or cite to him?



Hi @deborahc.vssqy6,

I’ve DM’d you to see if we can streamline the conversation.


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