What is the difference between Sprint APNs?

[ingenium]

So it seems there are at least 3 Sprint APNs: n.ispsn, r.ispsn, and x.ispsn.

I remember seeing n.ispsn on some of my older devices. I have a hotspot from Calyx (via Mobile Citizen) that has a Sprint account that I can log into, and it's using r.ispsn. My Pixel 2 XL is using x.ispsn.

Does anyone know what the difference is between them? My only guesses are that n.ispsn is "native", and r.ispsn is "reseller". Or perhaps n.ispsn is NATed via CGNAT and r.ispsn is "routed" meaning a public IP? I have confirmed that the hotspot that uses r.ispsn is assigned a public, routable IP. But that doesn't answer what x.ispsn is. My phone with x.ispsn is assigned a NATed IP.

[belusnecropolis]

R=routable, N =Non routable X not sure. r.ispsn devices receive a routable ivp4 address.

[ingenium]

R=routable, N =Non routable X not sure. r.ispsn devices receive a routable ivp4 address.

Do you know if you can change a device with n.ispsn to r.ispsn to get a routable IP with it?

Sent from my Pixel 2 XL using Tapatalk

[belusnecropolis]

4 minutes ago, ingenium said:

Do you know if you can change a device with n.ispsn to r.ispsn to get a routable IP with it?

Sent from my Pixel 2 XL using Tapatalk
 

I believe that would take a plan or SoC change, this is a great question but I am not sure. 

I know you can add a public IP address but that is not necessarily routable as you will hit that carrier NAT.  I have noticed there were some n.ispsn routers handed out over the last year; I believe they were the newer 910 hotspot but they were recently switched over to r.ispsn on the mysterious "backend" we are here trying to learn about. It caused quite the nasty outage for some folks for a few days.

[Kearney]

X.ispsn is ipv6 only.  No ipv4.  On phones using this apn 3g takes care of ipv4 and lte takes the ipv6. 

[ingenium]

X.ispsn is ipv6 only.  No ipv4.  On phones using this apn 3g takes care of ipv4 and lte takes the ipv6. 

Not true. My phone uses x.ispsn and I have verified that I have a non-routable (ie NATed) IPv4 address and a routable IPv6 address assigned. It's possible it dictates which pool of NATed IPv4 addresses it uses, but both are assigned for use on LTE.

Sent from my Pixel 2 XL using Tapatalk

[Kearney]

16 hours ago, ingenium said:

Not true. My phone uses x.ispsn and I have verified that I have a non-routable (ie NATed) IPv4 address and a routable IPv6 address assigned. It's possible it dictates which pool of NATed IPv4 addresses it uses, but both are assigned for use on LTE.

Sent from my Pixel 2 XL using Tapatalk
 

Sorry for the misinformation then.  My mistake.  I've tried multiple sim cards out of phones using the x.ispsn apn on my LTE modem and it never assigns an ipv4 address.   Are you sure it's not just a local ipv4 address assigned by the phone and tunneled over ipv6?

 

I found this while digging around in another forum.

 

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Albany889

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Message 41 of 61

 

Re: Moto E4/E4 Plus Issues on Sprint

‎11-30-2017 02:42 PM

It is possible that sprint variant E4 has a different and optimized setting of APN.

 

 

 

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lenovoma

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Message 42 of 61

 

Re: Moto E4/E4 Plus Issues on Sprint

‎11-30-2017 02:53 PM- edited‎11-30-2017 03:05 PM

It could be APN (not accessible with Sprint's configuration menu, but reports say if you insert another GSM network SIM you can poke it). However, the only setting that could be "wrong" would be "APN protocol." The options are: "IPv4", "IPv4/IPv6", "IPv6." APN's might be stored on SIM. Where did you guys get your SIM's, from Sprint, or Boost/Twigby? 

 

It could also be broken 464XLAT (NAT46) in the Moto OS itself.

 

 

 

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jp0213x

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Message 43 of 61

 

Re: Moto E4/E4 Plus Issues on Sprint

‎11-30-2017 02:55 PM

This is my first unlocked phone on sprint and I found out first hand they will not help and will point you back to the manufacture.  I'm not in a hurry to purchase a replacement phone for now, but this problem was a real deal breaker for me. Rule of thumb for me is to test any new phone I get right away and make sure it does everything my older does. I am not back to my rooted s4 cyogenmod until the problem is address or keep an eye out for another phone. I would like the s8 active but refusing to pay that kind of money for a phone when the e4 plus does the same thing for cheap.

 

 

 

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jp0213x

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Message 44 of 61

 

Re: Moto E4/E4 Plus Issues on Sprint

‎11-30-2017 02:57 PM

My sim card was from a sprint store, a coporate store. The 3rd party sprint stores are clueless.

 

 

 

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Albany889

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Message 45 of 61

 

Re: Moto E4/E4 Plus Issues on Sprint

‎11-30-2017 06:17 PM

My sim card was from Sprint.com. It can be considered as an official card from Sprint. But if I remember correctly, my IMEI was recognized as iPhone 8/8 plus at some point when purchasing or activating the sim card.

 

 

 

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lenovoma

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Message 46 of 61

 

Re: Moto E4/E4 Plus Issues on Sprint

‎12-01-2017 10:33 PM

I did some further testing and my conclusion is the following:

 

1. Sprint is pushing us a network profile that is ipv6 only, ipv4 is completely disabled en route from the phone to the Sprint network, although they do implement a NAT64 on their end so as to allow reaching the ipv4 network on the other side. You can see this in effect if you open up a browser and type in an address like www . google . com, where it works, but if you type in its one of its many corresponding ipv4 ip addresses, for example, 

172 . 217 . 13 . 228, it does not work. Even in a browser. This tells us that the only reason any app works at all with ipv4 on Sprint is because they are going through Sprint's translating DNS server.

 

2. The Moto E4 is broken, having either not included or not started the Android built-in CLAT service (client 4-to-6 translation) on the phone. Normally this service, part of native Android since Jelly Bean according to Wikipedia, would allow apps that require ipv4 literals to be able to route on an ipv6 only network by creating a fake ipv6 address.

 

It is a combination of these two that result in our phones not working on Sprint. People have had issues on T-Mobile in the past on other phones as well when they switched over to ipv6, but at least T-Mobile lets you put in APN settings to force it to ipv4, Sprint does not, as Sprint insists on provisioning all your connection settings over-the-air.

 

What would be a very interesting test to try is to get a T-Mobile SIM and set the APN settings to ipv6 only, and see if the unlocked Moto E4 can route packets to ipv4 literal addresses (or equivalently if all the streaming apps work). If that does not work either, then we know the Moto software has a broken implementation of 464XLAT. I suspect it does not work. As for phones that have no problem on Sprint, either they have the correct software, or Sprint is sending them profiles with ipv4 enabled as they are "legacy" phones.

 

The good news is that eventually, the apps will get updated and work over ipv6. They have to do that for iOS already, but they may be dragging their feet on Android.

 

The bad news is I suspect neither Sprint nor Motorola is interested in solving this problem."

Edited August 5, 2018 by Kearney

[ingenium]

Sorry for the misinformation then.  My mistake.  I've tried multiple sim cards out of phones using the x.ispsn apn on my LTE modem and it never assigns an ipv4 address.   Are you sure it's not just a local ipv4 address assigned by the phone and tunneled over ipv6?

It's the same IP range I normally see from Sprint. It is suspicious that it starts with 192, but that's the range I've seen assigned for a long time. This was also while connected to my Airave.

Sent from my Pixel 2 XL using Tapatalk

[Kearney]

I tried to edit my last post to include a quote I found on the forum that relates to this but I think I messed up the edit.  

[ingenium]

I tried to edit my last post to include a quote I found on the forum that relates to this but I think I messed up the edit.  

Hmm. I mean the APN settings show IPV4V6, which I think is default full stack. IPv6 only I believe uses IPV6 (I setup a T-Mobile APN this way once, and I received only a v6 address and it tunneled v4).

Typing in an IPv4 address works fine, but this would work even with 4to6. If Google wasn't working on that address in your last post, it's likely because of the way they have their webserver setup (you can set it so it requires a domain name in the request to know which site you want. This is normal for hosting multiple domains on a single IP, especially behind a load balancer. Called SNI).

For what it's worth, it's possible LTE modems are only able to get either a v4 or a v6 address but not dual stack on Sprint. I have a Sierra Wireless MC7455 using r.ispsn, and I can only get a v4 address on it even though it's setup for dual stack and that APN should give out both.


Sent from my Pixel 2 XL using Tapatalk

[ingenium]

It looks like 192.0.0.1 - 192.0.0.7 is a set of IPs reserved for DS-LITE: https://mxtoolbox.com/SuperTool.aspx?action=arin%3a192.0.0.4&run=toolpage 

We need an IPv4 sample from a device using the i.ispsn APN to see if it's assigned an IPv4 address in this range or a different range. It's possible that i.ispsn uses their legacy carrier grade NAT (perhaps with no IPv6 assigned to the device?), and x.ispsn uses DS-LITE.

DS-LITE is a way to tunnel IPv4 within IPv6 https://www.juniper.net/documentation/en_US/junos/topics/concept/ipv6-dual-stack-lite-overview.html and https://www.networkworld.com/article/2232181/cisco-subnet/understanding-dual-stack-lite.html So something like 4in6 + carrier grade NAT.

I'm guessing that this may have to do with Sprint's extensive use of IPSec tunnels. I read previously that you can't do dual stack over an IPSec tunnel, it's either IPv4 or IPv6. You can get around this by encapsulating the traffic in a different protocol like GRE, but it adds more overhead. So transitioning their backend network to IPv6 only makes sense (only have to worry about IPv4 at the entry/exit points for the network).

For devices like my Airave, which are connected via IPv4 (Verizon Fios is still IPv4 only...), that means that the phone is assigned an address in the 192.0.0.1-192.0.0.7 range, which is then encapsulated in IPv6, which is then encapsulated back to IPv4, encrypted and encapsulated into UDP, and sent over the VPN. No wonder the MTU on Airaves and Magic Boxes are so low, so many encapsulations...

So I wonder if this also means that devices that are assigned routable IPv4 addresses (r.ispsn) also have this v4 -> v6 encapsulation for transit over Sprint's network?