On Text Message SPAM and SIM Farms

SIMsBetter SMS SPAM Blocking Coming to the UK…

Interesting to learn that one of the large UK networks has a new product coming online soon – automated detection and blocking of SIM Farms and grey routes. (Grey routes being non-interconnected routes).

So a new product that most customers will have no awareness of at all, aside from hopefully fewer junk texts. Supposedly it’s able to detect, and block, SIM farms far more quickly and successfully than in the past.

For phone owners this is great as it will reduce some of the volume of PPI spam and other such annoying garbage.

For the legitimate players in the industry this is also great as it will cut down on the folks offering unfeasibly cheap (but inherently unreliable) message sending, and blackening the name of the whole sector as a result of the spam and garbage they happily push out.

For the most part, given the type of traffic often carried on negligible cost routes, it will lead to less garbage on the networks.

Of course we have to wait until it’s activated and see if it lives up to the promise.

What’s a SIM Farm Anyway?

Simply a bank of mobile GSM devices which connect to the network just like a mobile phone, and contain a SIM (frequently a PAYG, unlimited messaging SIM). Given the inclusive messages it’s no surprise the pricing can get ridiculously low and it appear quite attractive.

So What’s the Problem?

no signalWell apart from the fact you’re squarely breaching the mobile networks’ terms and conditions (they all have fair use clauses and restrictions that specifically exclude application to person and SIM farm traffic from their free messaging bundles)

There’s a number of issues with the common SIM farm solutions, here’s some of the usual issues:

  • Branding – do you really want to send your business message from a random number that will change over time? Far better to have a consistent monthly offer from “ABC Pizza” or whoever.
  • Numeric source addresses only. No longer can you send your messages as being from “Smith Dentist” etc, but from a random number that will be from whichever SIM was used to send your message.
    Chances are in six months when you send next reminder it will be from a different (and random) number as the first one is long since blocked. Likewise if you’re sending a large campaign it may be split over several SIMs – meaning different customers will receive messages from different numbers.
  • Being GSM SIM based, you’re connecting via a single point of failure which is the local network tower. No backup routes here, no automatic failover in the event of problems.
  • Speed. More precisely the lack of it. The reason SIM farm operators have banks of hundreds of GSM modems is that’s necessary to get an adequate throughput – a single SIM/number can typically only send 1 text a second. Compare that with the hundreds of messages a second or more possible via SS7 and interconnect routes.
  • Assorted Game Playing to avoid being detected as “not a person with handset”. These can variously include letting SIMs rest a while between sending bursts, adjusting throughput to not trigger spam and abuse detection and other forms of traffic shaping which are all going to reduce the overall throughput. Leading to needing more SIMs in the farm in order to meet messaging requirements.
  • No Receipts. It’s very uncommon to be able to get delivery receipts via SIM farms. So you have to trust the business to have sent all the messages they’ve charged you for. Yet they’re squarely and deliberately breaching the network terms and conditions to offer the service in the first place. Is it wise to place trust here? Well that’s for you to decide.
  • Tower undergoing maintenance or having capacity issues? You’ll not be sending any messages then.

How Should it be Done?

For reasons of reliability and speed, you should hope that your SMS provider provides multiple, redundant connections.

Mobile networks are large, complicated things. Within a network there will be many points of entry and exit with messages flowing into and out of the system. It’s not uncommon for problems to affect only part of a network, or a particular data centre or access point.

You would hope that your provider can provide more than one route to a particular network in the event of issues. In the case of a problem with a particular network they can then try alternative routes in order to find one still working successfully.

We can provide scalable, sustained throughput of hundreds of messages a second.

We have redundant interconnects to several operators and networks, and SS7 connections direct into a mobile network.

Routes are chosen to ensure maximum reliability and deliverability. Alternative routes are used immediately delivery problems are discovered.

World Text have built a network with redundant connections based around a need for reliability.

It’s one of the reasons we’re chosen by SARCALL for UK and Ireland Search and Rescue operations, and also used by UK Emergency Services.