CGNAT, Web proxy and other limitations of mobile broadband

Greetings all.

I've been experimenting with mobile broadband as a possible alternative to a 50 Mb Virgin Media service and, so far, I've just been looking at Three and Smarty (the sub-brand of Three). I have a Teltonika RUT240 mobile router feeding a pfSense router/firewall, with a LAN behind it and an IPv6 tunnel from Hurricane Electric. I make use of VPNs (both in and out) and I have a VPS or three for general playing. So not entirely an average user.

I have a free Three 200MB-a-month SIM for testing and I've found this works well, giving me a public IP address when specifiying the APN as 3internet (a CGNAT shared address with an APN of three.co.uk), no Web proxy and, as far as I can see, no filtering or other restrictions on use.

I was tempted by the £18.75 unlimited SIM from Smarty because the price is attractive and the only commitment is a month, so ordered one a few days ago. I'm a little disappointed to find that it forces a CGNAT connection (it accepts the 3internet APN but still gives me a private IP address with a shared public address) and also forces all tcp/80 HTTP traffic through a proxy. The CGNAT, of course, causes difficulty with inbound connections but an acceptable workaround is to use a tinc/rinetd tunnel on a VPS, where the VPS's fixed IP address is effectively mapped to my LAN.

Still, I'd prefer a "clean" connection without the ISP fiddling with my data and wondered if the assembled experts could suggest any other providers worth looking at. I'm especially interested in identifying limitations before buying a service and the various providers' customer service people don't seem partricularly technical. (I asked Smarty about CGNAT before buying their SIM and they simply didn't understand the question.)

That's enough waffle! Any suggestions, comments, etc will be most welcome.

Edited by ashdown (Fri 27-Sep-19 21:46:06)

I found a VPS IP is often seen as blocked by streaming sites and iplayer. One solution to that is an L2TP tunnel to AAISP. they don�t do encryption. Or you could use a VPN provider such as NordVPN as most routers have OpenVPN support now.

On the ISP side the cheapest that works probably worthwhile, but radio is always a shared medium. As you have the choice of VM what is the reason for moving to radio?

Thanks for the comments. Perhaps I'm lucky but I can stream Netflix, BBC, etc through a VPN to my VPS without any issues. VM's service is fine from a technical POV but I'm getting fed up with their twice-a-year price rises and the need to renegotiate price every year to keep it half-reasonable. Talking to their CS is a really awful experience, especially with a typical hour or so wait in a queue. Mobile broadband is around half the cost and that's attractive. I do like AAISP and the L2TP tunnel is a good technical solution to provide fixed IPv4 and IPv6 but the extra tenner-a-month reduces the price incentive.

Just go for a the Three unlimited SIM .

If you want bargain basement, i.e. Smarty, you've just told us why it's so cheap.

Edited by RobertoS (Fri 27-Sep-19 23:45:48)

In reply to a post by RobertoS:

Just go for a the Three unlimited SIM .

If you want bargain basement, i.e. Smarty, you've just told us why it's so cheap.

You are saying Smarty forces all the web traffic through a proxy but three itself does not?

Interested as I am also looking at switching my 50mb fttc over to 5g with three in the new year some time as it will result in a cost saving as well as hopefully a big speed increase, BUT I don't want them messing with my traffic. I will also consider EE, voda, o2 but when it comes to 5g it seems unlikely anyone will compete with three (assuming I can get a half decent signal which I don't know yet as I dont think 5g is here yet so I will end upi having to test them all).

Edited by Ewok (Sat 28-Sep-19 09:58:48)

In reply to a post by Ewok:

You are saying Smarty forces all the web traffic through a proxy but three itself does not?

It is possible they do, it is a cut price product. Would be worth running a transparent proxy discovery tool. I thought with most websites now encrypted using TLS ; there was little point in caching proxies.

Interested as I am also looking at switching my 50mb fttc over to 5g with three in the new year some time as it will result in a cost saving as well as hopefully a big speed increase, BUT I don't want them messing with my traffic. I will also consider EE, voda, o2 but when it comes to 5g it seems unlikely anyone will compete with three (assuming I can get a half decent signal which I don't know yet as I dont think 5g is here yet so I will end upi having to test them all).

Mobile networks have to manage traffic all the time. They have towers with generally 3 cell sites in fixed areas. If there is a congregation of users on one of the cells, and not in the other two, then you can get an imbalance.

LTE (4G) as a system is quite good at keeping service but degrading slowly, so you get slower speeds rather than no connection. The old UMTS (3G) and GSM/GPRS (2G) systems would fail in load situations. Often seen in London railway stations at 5pm!

I am finding quite often with EE on 4g in/around London with my S8+ that I just cannot get a connection. The signal shows 2 bars or more and 4g or 4g+ but trying to load something just fails. I assume it's just over capacity and is not letting me connect to anything, eventually I will be able to connect ok after enough tries. I had it a lot in Aldgate yesterday morning, it is one of the other reasons I am looking at switching to three when 5g is a bit more widespread next year (as I would hope 5g will not have the issue).

Anyway I don't want to take op's thread off topic

In reply to a post by Ewok:

I am finding quite often with EE on 4g in/around London with my S8+ that I just cannot get a connection. The signal shows 2 bars or more and 4g or 4g+ but trying to load something just fails. I assume it's just over capacity and is not letting me connect to anything, eventually I will be able to connect ok after enough tries. I had it a lot in Aldgate yesterday morning, it is one of the other reasons I am looking at switching to three when 5g is a bit more widespread next year (as I would hope 5g will not have the issue).

It could be load, depending on which parts of London. EE has a lot of capacity available, and Vodafone are second, in 4G spectrum. One of the reasons for 5G is that it increases capacity dramatically.

Every smart device remains connected, even when in standby (screen off) in your pocket, waiting for a call, or a WhatsApp, or iMessage, or some notification. These connections take up "spaces" on the mast you are connected to, and the numbers for connected devices per square kilometre are approximately 3G=400, 4G=4000, 5G=1,000,000

In many countries more masts are being added, smaller, unobtrusive. In the UK our planning laws and councils tend to prevent masts. The Mayor of London is asking for more to be rolled out:
https://www.theregister.co.uk/2019/09/27/mayors_offi...

Edited by jchamier (Sat 28-Sep-19 10:37:52)

I tried smarty first and had big problems with packet loss and some streaming services just wouldn't work, switched to three and the problems disappeared, I'm convinced smarty are doing something with their network to cause this. As said there is a reason it's cheap

Yeah I wouldn't consider any 3rd party for reasons like that, plus I have always assumed the network owner is going to prioritize their own customers over other companies renting their network as it wouldn't make sense not to so I would be going to one of the big 4 only, depending which one gives me the best speeds at home.

I will switch my mobile too but that probably will just go to Three since I won't be restricted to one location on mobile and they should generally be the fastest for 5g (by some distance based on spectrum!) as I move around. For example there would be no point switching my mobile to say Voda or o2 just because one of those gave me slightly higher speed at home than three where I don't really need it (since I will have home broadband anyway on whatever the fastest one is), when it would be likely to give me lower speeds than three everywhere else where I would need it more. I am kinda hoping three is also the fastest at home as I might get a better deal switching home broadband and mobile to them but I will see where things are at in April when I get a new phone and look to see what kind of 5g I can get at home by then, if any. Hopefully the 5g routers will have also moved on a bit by then and be generally better than now.

In reply to a post by jchamier:

In reply to a post by Ewok:

I am finding quite often with EE on 4g in/around London with my S8+ that I just cannot get a connection. The signal shows 2 bars or more and 4g or 4g+ but trying to load something just fails. I assume it's just over capacity and is not letting me connect to anything, eventually I will be able to connect ok after enough tries. I had it a lot in Aldgate yesterday morning, it is one of the other reasons I am looking at switching to three when 5g is a bit more widespread next year (as I would hope 5g will not have the issue).

It could be load, depending on which parts of London. EE has a lot of capacity available, and Vodafone are second, in 4G spectrum. One of the reasons for 5G is that it increases capacity dramatically.

Every smart device remains connected, even when in standby (screen off) in your pocket, waiting for a call, or a WhatsApp, or iMessage, or some notification. These connections take up "spaces" on the mast you are connected to, and the numbers for connected devices per square kilometre are approximately 3G=400, 4G=4000, 5G=1,000,000

In many countries more masts are being added, smaller, unobtrusive. In the UK our planning laws and councils tend to prevent masts. The Mayor of London is asking for more to be rolled out:
https://www.theregister.co.uk/2019/09/27/mayors_offi...

At my main place of work we see this on busy days when there are thousands of handsets connected to our local cell site. Signal is fine, however you get stumbles where things just freeze, and calls drop out, or go silent. The O2 cell site in question was located specifically to cater for our buildings, and has been setup with many cells & sectors all pointing towards narrow and specific areas. The extra bandwidth O2 aquired has helped, however the freezing issues still persist at busy periods.

Edited by gary333 (Sat 28-Sep-19 10:54:16)

In reply to a post by gary333:

At my main place of work we see this on busy days when there are thousands of handsets connected to our local cell site. Signal is fine, however you get stumbles where things just freeze, and calls drop out, or go silent. The O2 cell site in question was located specifically to cater for our buildings, and has been setup with many cells & sectors all pointing towards narrow and specific areas. The extra bandwidth O2 aquired has helped, however the freezing issues still persist at busy periods.

Yes, my office is in the middle of nowhere, and we have a Vodafone mast on the roof. Without that, there would be no signal on any network! I've not seen the freezing issue, but we are probably less heavy users, despite having got rid of all the desk phones, as we all sit at laptops

In reply to a post by Ewok:

I will switch my mobile too but that probably will just go to Three since I won't be restricted to one location on mobile and they should generally be the fastest for 5g (by some distance based on spectrum!) as I move around.

Just be aware that 5G is evolving fast. At the moment it is "NS" (Non Standalone) and needs a 4G signal at the same time to work. (This is the same in the US for Verizon/AT&T/T-Mobile etc). All the networks are busily deploying their 5G equipment, but the phones will take a while to catch up. There is a reason the 5G handsets are separate models to the 4G handsets, (e.g. Samsung S10 5G) as with all new technology, the 5G chips are power hungry.

Exactly why I am waiting until April to upgrade my phone. I am hoping that the S11 which will be out in March has a newer much more efficient and faster 5g chip in it as it should be 2nd gen by then and not the same as the ones out this year. Hopefully whatever chip ends up in it will also support standalone so it is future proofed and I won't need another phone for a couple of years. Either way I am upgrading in April anyway since my S8 will be 3 years old.

Edited by Ewok (Sat 28-Sep-19 11:23:00)

In reply to a post by Ewok:

In reply to a post by RobertoS:

Just go for a the Three unlimited SIM .

If you want bargain basement, i.e. Smarty, you've just told us why it's so cheap.

You are saying Smarty forces all the web traffic through a proxy but three itself does not?

No, I�m not . I�m saying that I can�t recall anybody people on this forum who has gone to Smarty on the basis of it being the same as Three but cheaper and not been disappointed for one reason or another. Smarty complaints make me think �there�s another�.

�Three� complaints make me wonder where the problem lies; with Three or the customer not having done their homework about speed and latency variations before purchase.

In my case, which opened up the whole possibility on this forum of ditching landline altogether with the Three Black Friday £20 unlimited SIM last year, I first tested with a £1 SIM from the paper shop, then went for the £20 one in November, and ditched my AAISP broadband after a week or so as the cost of regaining it was minimal.

Similarly the extra cost of the Three SIM for 12 months over my previous EE mobile contract would have been irrelevant and easily written off if I had wanted to go back to EE at the end of it.

People seem often to forget what they are already paying on mobile when comparing a complete move to it from landline. Unlike when switching landline supplier.

I ran through Christmas on Three and was perfectly happy, so then dropped my landline. No regrets! Since when I�ve installed a security camera, with more to come, so have also bought the Three HomeFi as I want near-instant cloud storage for the recordings. I don�t trust home recording from the cameras not to walk at the same time as whatever else is stolen.

I know nothing about proxies. Just that except for people who seem not to have tested speeds before moving to Three there have been very few complaints compared to the ones on Smarty. My theory is that Smarty are simply loading their rented bandwidth more heavily.

That could improve over time of course, as Three increase their own capacity and may lower their third-party (vISP) prices.

In reply to a post by RobertoS:

In reply to a post by Ewok:

In reply to a post by RobertoS:

Just go for a the Three unlimited SIM .

If you want bargain basement, i.e. Smarty, you've just told us why it's so cheap.

You are saying Smarty forces all the web traffic through a proxy but three itself does not?

No, I�m not . I�m saying that I can�t recall anybody people on this forum who has gone to Smarty on the basis of it being the same as Three but cheaper and not been disappointed for one reason or another. Smarty complaints make me think �there�s another�.

�Three� complaints make me wonder where the problem lies; with Three or the customer not having done their homework about speed and latency variations before purchase.

In my case, which opened up the whole possibility on this forum of ditching landline altogether with the Three Black Friday £20 unlimited SIM last year, I first tested with a £1 SIM from the paper shop, then went for the £20 one in November, and ditched my AAISP broadband after a week or so as the cost of regaining it was minimal.

Similarly the extra cost of the Three SIM for 12 months over my previous EE mobile contract would have been irrelevant and easily written off if I had wanted to go back to EE at the end of it.

People seem often to forget what they are already paying on mobile when comparing a complete move to it from landline. Unlike when switching landline supplier.

I ran through Christmas on Three and was perfectly happy, so then dropped my landline. No regrets! Since when I�ve installed a security camera, with more to come, so have also bought the Three HomeFi as I want near-instant cloud storage for the recordings. I don�t trust home recording from the cameras not to walk at the same time as whatever else is stolen.

I know nothing about proxies. Just that except for people who seem not to have tested speeds before moving to Three there have been very few complaints compared to the ones on Smarty. My theory is that Smarty are simply loading their rented bandwidth more heavily.

That could improve over time of course, as Three increase their own capacity and may lower their third-party (vISP) prices.

You willfully keep ignoring that Smarty are Three and not a third party.

Smarty are not renting capacity from Three. Smarty are giving an equivalent service to that which you get directly via Three using a handset and the three.co.uk APN. What this means is that you will be behind CGNAT - just like on three with a handset, and for that matter pretty much all other providers such as EE & O2 which give you CGNAT regardless of whether you are on a handset sim or a mobile data package.

I am more than happy with Smarty. I took out a Three contract in January this year and the service was [censored] due to network issues. When Smarty appeared with the £18.75 unlimited data and no contract (and cruicially no credit check as wasn't happy having two for phones within 6 months) I decided to give it a try. The nework issues from Three appear to have been mitgated to some extent, and I now find speeds on both Three & Smarty to be good enough.

I've tested very recently with various Three sims (PAYG and monthly, along with data only plans) and there is no speed differential between Three and Smarty. The primary difference between Three & Smarty is that Smarty only offer CGNAT'd traffic. To most people this doesn't matter, but does need to be a consideration. However, if you are not bothered by CGNAT then there is no other difference between Smarty & Three.

In reply to a post by gary333:

You willfully keep ignoring that Smarty are Three and not a third party.

LOL .

There you are completely wrong.

I didn't know that! Why would I wilfully mislead people, given I have been providing well-reputed advice on xDSL here for well over thirteen years?

It don't think it makes much difference to what I said though. The fact you are happy with Smarty doesn't remove from consideration the many who have posted about disappointment.

However it is odd given your post that for you Smarty initially proved better than Three. Could that be that there is a software fixed, (configuration variable), split of mast capacity and that on yours the Smarty allowance was under-utilised and the Three part over-utilised? Which amounts to the same as I was suggesting, in reverse.

There are many differences between the two services, from the research I just carried out to check your basic statement was correct. It is far from being just the CGNAT or not.

Incidentally on my HomeFi router I can swap at will between 3ireland.ie and 3internet. IIRC one is CGNAT and the other isn't. On my phone, 3ireland.ie and three.co.uk.

I assume the second of each are the same. The Ireland ones are much snappier in use, though speeds and latency variations very similar. Possibly the speed and latency are predominantly mast dependent.

In reply to a post by RobertoS:

In reply to a post by gary333:

You willfully keep ignoring that Smarty are Three and not a third party.

LOL .

There you are completely wrong.

I didn't know that! Why would I wilfully mislead people, given I have been providing well-reputed advice on xDSL here for well over thirteen years?

It don't think it makes much difference to what I said though. The fact you are happy with Smarty doesn't remove from consideration the many who have posted about disappointment.

However it is odd given your post that for you Smarty initially proved better than Three. Could that be that there is a software fixed, (configuration variable), split of mast capacity and that on yours the Smarty allowance was under-utilised and the Three part over-utilised? Which amounts to the same as I was suggesting, in reverse.

There are many differences between the two services, from the research I just carried out to check your basic statement was correct. It is far from being just the CGNAT or not.

Incidentally on my HomeFi router I can swap at will between 3ireland.ie and 3internet. IIRC one is CGNAT and the other isn't. On my phone, 3ireland.ie and three.co.uk.

I assume the second of each are the same. The Ireland ones are much snappier in use, though speeds and latency variations very similar. Possibly the speed and latency are predominantly mast dependent.

I agree that you do post really useful things, and I am not questioning your integrity, more your attention as I have pointed the relationship of Smarty & Three out to you directly at least twice over the last month or so.

As discussed previously the APN is not the primary driver on Three to what access you get to the network. This is not the case on networks such as O2 and Vodafone as if you put the wrong details in you simply get no network access to data.

With three you can put anything in the APN field such as "iwantmorespeedplease" and what the network does is give you the generic handset access profile. This means you get CGNAT and you also get the proxying of the http data as described by the original poster. Putting 3ireland in is the same as putting in three.co.uk.

Only when "3internet" is input in to the APN field does the network allocate the public IP, this results in lower ping times by around 10ms for most, but crucially you are no longer bound by the CGNAT.

Also, I never said that Smarty had a better connection. I said that Three network was poor in my area when I took the contract out. The signal and throughput between the two is the same so this shows that Three have resolved the issues in my area.

Additionally what other differences did your research find between Three and Smart? As I mentioned above the Smarty service should be a like for like experience as you get on Three using the standard handset three.co.uk APN.

If you think it isn't I would like to know why as I don't believe I am incorrect on this one.

https://www.simsherpa.com/networks/compare/smarty-vs...

In reply to a post by RobertoS:

https://www.simsherpa.com/networks/compare/smarty-vs...

I mean't from a network access point of view that would effect our day to day usage of Smarty & Three when using within a 4G router, rather than the bells and whistles.

That link shows WiFi calling (wouldn't be used in a router) and Easy Jet upgrades. The go binge isn't valid on the unlimited data plan, as well it's unlimited

In reply to a post by Ewok:

You are saying Smarty forces all the web traffic through a proxy but three itself does not?

That is my experience, yes. With the proviso that Smarty forces all HTTP (port 80) web traffic through a proxy but they can't do so with HTTPS (port 443). As the Web is increasingly HTTPS, this is perhaps less of an issue than it used to be. It's simple to test:

On my £18.75 Smarty SIM with an APN of 3internet,
"curl --silent http://ipecho.net/plain" returns the IP address of a proxy,
"curl --silent https://ipecho.net/plain" returns a CGNAT shared address
and my router shows a private IP address used inside Three's network.

On my free 200MB-a-month Three SIM, with an APN of 3internet, both those lookups return the public IP address seen by my router.

I see that Three are now offering an unlimited SIM for just £16 per month with a Huawei B311 HomeFi router to existing customers, but on a 2-year contract, which is a rather long commitment. I wonder if they'd reduce that price further without the router.

Edited by ashdown (Sat 28-Sep-19 14:43:12)

In reply to a post by ashdown:

On my free 200MB-a-month Three SIM, with an APN of 3internet, both those lookups return the public IP address seen by my router.

I believe Three is the only mobile ISP that offers public IP without CGNAT. The others (EE,Vodafone, O2) are all CGNAT and have been for decade or more. I suspect with the lack of IPv4 addresses, that Three will have to decide what to do as they grow in customers sooner rather than later.

EE offers a public IPv6 as well as CGNAT IPv4.

In reply to a post by gary333:

I agree that you do post really useful things, and I am not questioning your integrity, more your attention as I have pointed the relationship of Smarty & Three out to you directly at least twice over the last month or so.

Being the same company, doesn't mean its the same product, or team managing it. Look at GiffGaff and O2.

In reply to a post by jchamier:

I believe Three is the only mobile ISP that offers public IP without CGNAT. The others (EE,Vodafone, O2) are all CGNAT and have been for decade or more

Thank you - that's useful information. Although there are technical ways of avoiding the drawbacks of CGNAT, I think I'll have to rule out all the other providers on these grounds (although I'd be happy with IPv6). In case it's of interest to others, I've noticed that Three regards a user of its free 200 MB-a-month SIM as an "existing customer". So, to benefit from Three's discounted offers to existing customers, such as the £16 per month unlimited data SIM, all one has to do is order a free 200MB SIM and register an account.

Edited by ashdown (Sat 28-Sep-19 18:07:58)

In reply to a post by jchamier:

In reply to a post by gary333:

I agree that you do post really useful things, and I am not questioning your integrity, more your attention as I have pointed the relationship of Smarty & Three out to you directly at least twice over the last month or so.

Being the same company, doesn't mean its the same product, or team managing it. Look at GiffGaff and O2.

Yep certainly truth in that the management structures are not the same, however in this instance Smarty are an 'unbranded' Three service rather than a Three MVNO. Three do have MVNO's such as ID Mobile and Superdrug and both have different business models, associated network access and do pay for an agreed level of service from Three. Thus the level of service from these MVNO's is determined and not equal to that of Three direct.

Gff Gaff was created as a proof of concept (with the majority buy in coming from the Telefonica board). Where the story between Giff Gaff and Smarty diverges is Giff Gaff was only allowed by the O2 UK board if the business were kept totally seperate and that this POC didn't detrimentally impact their (O2 UK) network, nor try and grab O2's customer base, or even mention there was any relationship to O2. This meant totally different reporting lines, seperate buildings and crucially their own financials. Giff Gaff was / is an MVNO and simply purcahsed 'blocks' from O2. O2's legacy of being made up of many different service providers made it relatively simple for O2 to create MVNO''s. Giff Gaff business case actually came from a person within O2's own product develpoment team - however the business case was about attracting a different type of customer and testing out a new customer interaction model, rather than testing out new technological / network related improvements. Over the years Giff Gaff has remained a totally seperate entity and as such even the customer centric learnings have not been fedback in to the mothership.

Smarty on the other hand reside in the same office as Three UK and are not being treated as the poor relation having links in to the various Three teams. Smarty has been setup by Three as a test bed to try out new ideas - be that process related, billing related or customer related. Smarty gives Three an opportunity to fail and it not be to public, nor affect the main brand. Smarty feeds in to both the Three financals and is influenced by Three's marketing and product development teams.

One experiment could be proxying traffic to see if that reduces transit fees.

Can I just check if the situation remains the same - ie on SMARTY
- Proxying of traffic (presumably partly in support of 'endless') - that sounds problematic
- CGNAT even on 3internet APN

I signed up to 3 MBB (short term fill-in, 1 month) and was thinking of hopping over to smarty to reduce costs, but having just
- realised the CGNAT issues (external IP/forwarding)- not critical but annoying. less so with real ipv6 - which I presume you do get on smarty?
- had three's 'gobinge' disabled - which //seems// to have stopped messed up routing and restrictions of netflix, youtube etc - the bigger concern

I might just accept it's best to stick with 3 MBB sim

In reply to a post by planetf1:

Can I just check if the situation remains the same - ie on SMARTY
- Proxying of traffic (presumably partly in support of 'endless') - that sounds problematic
- CGNAT even on 3internet APN

I signed up to 3 MBB (short term fill-in, 1 month) and was thinking of hopping over to smarty to reduce costs, but having just
- realised the CGNAT issues (external IP/forwarding)- not critical but annoying. less so with real ipv6 - which I presume you do get on smarty?
- had three's 'gobinge' disabled - which //seems// to have stopped messed up routing and restrictions of netflix, youtube etc - the bigger concern

I might just accept it's best to stick with 3 MBB sim

No ipv6 on Smarty, and only CG-NAT. I've been using 700-800GB per month on Smarty and no issues with slowing down or anything like that from a data usage point of view. However, the Three network has been very poor over the last month. Since Sunday the network has been behaving much better so hopefully problems are starting to subside but speeds are still much lower than they have been pre February..

Thanks for the update ...

In reply to a post by bluecat1:

I tried smarty first and had big problems with packet loss and some streaming services just wouldn't work, switched to three and the problems disappeared, I'm convinced smarty are doing something with their network to cause this. As said there is a reason it's cheap

I just tried Smarty - for two days. Speeds akin to Three, but no public IP.
But the weird thing is that it kept changing IP address.
Not on a change of cell, all the time.

Normally you'd get an IP address and a few seconds later you'd get the next IP address along. Usually something like .....102 then ....103 and then the next minute you're back on ....102

This caused ssh and sftp sessions to freeze, but not disconnect until a timeout was reached.
I tried setting up a cron to wget a tiny file every 20 seconds, but that didn't help.

Setting the APN to a Three one didn't help.

I put a Three sim in and these problems persisted, because I'd left it on the Smarty APN. Switching to the Three APN fixed it.

Smart people won't choose Smarty for an internet connection. The voice calls are fine.

In reply to a post by bluecat1:

Normally you'd get an IP address and a few seconds later you'd get the next IP address along. Usually something like .....102 then ....103 and then the next minute you're back on ....102

Looks like this is primary driver of my issues on Smarty as well then, other than of course the fact HTTPS/TLS connections can just die.

I notice if I keep clicking 'refresh' of say: https://whatismyipaddress.com/ip-lookup , the IP address keeps jumping around.

No wonder Smarty has issues with some websites as I notice I can get logged out a lot given the source (my) CGNAT IP address changes randomly. Explains why a VPN works perfectly then as you tunnel through this and have the same IP consistently then.

Edited by deleted (Thu 22-Oct-20 11:39:00)

In reply to a post by Anonymous1337:

No wonder Smarty has issues with some websites as I notice I can get logged out a lot given the source (my) CGNAT IP address changes randomly. Explains why a VPN works perfectly then as you tunnel through this and have the same IP consistently then.

Only poorly designed websites use your IP to log you out. Many internet connections have used proxies and changing IP addresses for years. CGNAT is not new, just most people haven't used it. At coprporate employer for example all internet goes through a web proxy, and the IP you get on a web page can change each refresh to a different one in the proxy group.

In reply to a post by jchamier:

In reply to a post by ashdown:

On my free 200MB-a-month Three SIM, with an APN of 3internet, both those lookups return the public IP address seen by my router.

I believe Three is the only mobile ISP that offers public IP without CGNAT. The others (EE,Vodafone, O2) are all CGNAT and have been for decade or more. I suspect with the lack of IPv4 addresses, that Three will have to decide what to do as they grow in customers sooner rather than later.

EE offers a public IPv6 as well as CGNAT IPv4.

Worth noting EE firewall IPv6 inbound, so you can't run anything on a EE IPv6 address just for info, in terms of incoming services. Certainly for 4G anyway, not sure if this changed for 5G, but EE are filtering all inbound in their network.