Smarty Data SIMs - Inbound network connections permitted?

[GrahamS_1715202]

I've not yet tried a Smarty Data-only SIM, but I'm wondering if anybody can confirm if they will allow incoming TCP connections from the internet (before I order one)?

I tried to do this with a Smarty voice SIM, but found that inbound connections were actively being blocked at the carrier level (i.e. the inbound packets never arrived at my LTE router, despite me being assigned a public IP address (i.e. not CGNAT).

I'm hoping this might be one of the differences between the voice and data plans on Smarty? Can anybody confirm?

Thanks, Graham.

[Chalkychap]

I have a data only SIM, which I use in a laptop. 

Not sure what inbound TCP ports you're planning to use, but a SMARTY data plan is just a 1-month commitment, so why not get a data only SIM to test? 

The only point I'd make is the SMARTY terms & conditions have sections stating unlimited data and voice plans are not intended as a substitute for a fixed-line ISP service, which is something they monitor on unlimited plans I'd guess.

[GrahamS_1715202]

Thanks Chalkychap, yeah I might just have to give it a go and see if it works. I can choose what ports I use, so if they block some of the standard ones, it's not a problem. The issue I had with the voice SIM was that it appeared they had an upstream firewall in place blocking all inbound (non-established) connections to the IP - at least for all the random ports I chose/tried! 😂

[GrahamS_1715202]

Well hopefully this information helps future folks - I used one of my bonus SIMs and signed up to a data plan. Unfortunately it behaves exactly like the voice plans in terms of incoming connections. I get assigned a public IP on my LTE router's WAN interface, but incoming connections are blocked.

This is pretty disappointing! 😥 

In light of the above, I can find absolutely no reason to sign up to Smarty's data plans - they are more expensive than the cheaper (per GB) voice plans, and offer no apparent benefits whatsoever. 

[GrahamS_1715202 · Accepted solution]

One last follow up.  It turns out that what I thought was a public IP, is actually not. My router was showing:

WAN IP Address: 100.104.232.210

Which to begin with, looked like a public IP to me and not CGNAT. However, on further research, it turns out, this is in fact not a publicly routable IP address and is equivalent to the 10.0.0.0/8 addresses we're used to seeing on CGNAT.

So in short, forget Smarty for broadband where you need to be able to receive incoming connections.