Teamviewer access on EE4G

[benphillips]

Hi,

We have had to put in a 4G broadband connection in an office because the standard landline broadband speeds are woeful. The 4G speeds on EE are much better and the internet connection is fine across the office. However, we have Teamviewer installed on some of the machines in the office to allow remote access, and Teamviewer does not detect an internet connection. We also have AnyDesk installed on one machine, and this constantly has the message "Trying to connect to network". It would appear that something is blocking these connections. Can anyone shed any light? We are using a Zyxel router rather than an EE router and so could make changes if necessary.

Any advice greatfully recieved!

[XRaySpeX]

Can't believe that! Many mobile router users have successfully switched down to IPv4 when they had an issue when it was IPv4/IPv6 combined. 

[mikeliuk]

Hi @benphillips ,

Would you be able to put that SIM into another router or phone to see if a different device gets an IPv4 address assigned by the service provide which shall not be named?

It doesn't sound correct to me that no IPv4 address is assigned. I would expect you to receive a 100.x.x.x address assuming it's a standard consumer SIM. I probably have no idea about business SIMs but I get the impression they may be assigned publicly routable IPv4 addresses but not statically assigned, until you are assigned something, you can't check either way.

[benphillips]

@XRaySpeX 

"Can't believe that! Many mobile router users have successfully switch down to IPv4 when they had an issue when it was IPv4/IPv6 combined."

Quite right too! I changed the settings back to IPv4 only again, and this time got a connection with an IPv4 address. Perhaps I was a little impatient last time. With an IPv4 address, Teamviewer and AnyDesk clients can connect correctly. Your suggestion re it being an issue with EE having issues with falling back to IPv4 addressed would appear to be the case.

I thank you for your time and responses, and I am very grateful.

[benphillips]

@mikeliuk 

As per my previous post, changing the APN settings to connect via IPv4 has worked this time. The router has got a 10.x.x.x address (it is an EE business SIM).

Thanks for your time and input.

[XRaySpeX]

Thanks! You're welcome 🙂 ! Glad I could be of assistance & it is now sorted.

[mikeliuk]

Hi @benphillips ,

Very glad you got that sorted.

I just wanted to flag for your attention that the 10.x.x.x range (i.e. 10.0.0.0/8) is a subnet reserved for private network usage and is used by many large enterprises for their own internal networks as it is one of the largest (if not the largest) such range reserved for such usage. https://en.wikipedia.org/wiki/Private_network

Therefore, in my personal opinion, the service provider should not be using IPv4 addresses within this range to assign to businesses as this could cause a misconfiguration of the network if the same range is used elsewhere within a business or enterprise. If there is any chance the network administrator is already using or may in the future choose to use IP addresses in 10.0.0.0/8, care must be taken when it comes to routing.

Hopefully this turns out to be a non-issue, perhaps if all other subnets are in the other private ranges. Good luck!

[XRaySpeX]

@mikeliuk : This is a non-issue.

---

@mikeliuk wrote:

Therefore, in my personal opinion, the service provider should not be using IPv4 addresses within this range to assign to businesses as this could cause a misconfiguration of the network if the same range is used elsewhere within a business or enterprise.

EE isn't & it won't cause issues on internal networks!

1. This 10.x.x.x IP is the external "public" IP assigned to the SIM device by EE's DHCP within its CGNAT regime.
2. EE is itself one of your many large enterprises using these 10.x.x.x IPs for their own internal networks behind the CGNAT.
3. Many other CGNAT'ing mobile networks will be doing the same thing; O2 for 1.
4. Even if the LAN behind the phone/router is using the same 10.x.x.x IP subnet they will not be confused or misconfigured. It's all taken care of by the local NAT translating an internal routing 10.x.x.x IP into an external EE CGNAT 10.x.x.x IP. I have had 2 fixed BB routing routers on the same 192.168.1.x subnet working seamlessly even if both of them give out IP 192.168.1.100, say, but to 2 diff devices. Same principle!
5. This 10.x.x.x IP is not the true external public IP (shared by CGNAT) seen by the rest of the Net. That may be gotten by WhatsMyIP type sites, not by looking in the About My Device settings.

[mikeliuk]

Making a note for people reading this in the future that Wiki summarizes the issue as follows:

"If an ISP deploys a CGN, and uses RFC 1918 address space to number customer gateways, the risk of address collision, and therefore routing failures, arises when the customer network already uses an RFC 1918 address space."

https://en.wikipedia.org/wiki/Carrier-grade_NAT

RFC 1819 may be found here: https://datatracker.ietf.org/doc/html/rfc1918

Edit: a particular risk is if the 192.168.0.0/16 subnet is too small for an office and 10.0.0.0/8 is used on the subnet which directly accesses the service provider's gateway.