What Are SMS Grey Routes, How They Can Hurt Your Business


It’s undeniable and truly understandable that businesses pursue to lower their costs and increase their benefits, but sometimes there are risky decisions that are lightly taken without evaluating the true cost.

In the SMS world (most of all in the A2P -or Application To Person- niche) this type of decision almost always involve choosing between the right kind of service provider to send thousands of text messages (for marketing purposes, most of the time), or take your business to a very cheap service provider that can provide “Grey Routes” to send them.

The sad truth is that although Grey Routes are an interesting technical topic to learn about, they provide no real use for your business, since the providers that use them will still charge you for messages that won’t be delivered when the carriers block them.

In this post we’re going to discuss what are grey routes, and how they could hurt your business (and everybody’s) in the end. Grey routes are a scam, and we are going to discuss why is that exactly and how do they work.

The WorldWide Telephone Network

Before getting into the commercial stuff, it is good to understand just a bit of technical stuff involved, so one can get an idea of the whole picture. We’ll make this short and sweet, we promise!

The telephone network (also called PSTN, for Public Switched Telephone Network) is a big world-wide network where telephone companies and subscribers (you, me, your neighbor, etc) are connected to each other.

One of the first protocols used in the telephony world was called R2, it was an analog protocol used to interconnect the different carriers and their switches, so one could call to any subscriber in the world from its own home.

The Telecom Network: SS7

In the 1970s a new protocol was put in place, this time full digital and it was called SS7 (Signalling System No. 7). It also takes into account the mobile network services, like SMS, and could interact with GSM and GPRS networks right from the very beginning.

Fun Fact: The 140 (and 160) character limit for a text message lies right here in the very heart of SS7!

How Do Telecoms Charge SMS

The very basic idea is that telecoms will not charge each other for SMS traffic. That’s right! Why? It has a very simple explanation, actually.

They expected at first that the traffic was going to be 2-way and between persons, meaning that if a client of a specific telecom sends a message to another client of a different company, they will get a reply back.

In this best-case scenario, both telecoms will make a profit by charging their own customers and thus the cost of the traffic between them will balance out in the end, avoiding the need of charging each other for the traffic that they were putting into each others network. Makes sense, right? It did for some time, at least.

So What are These Grey Routes?

Let us say that each telecom company in the world has what it’s called a Global Title that allows them to send and receive traffic from every other telecom in the world. This is how traffic is “routed” from one network to another.

Also, any telecom would accept traffic from any other globally registered telecom without any questions. Having a Global Title was enough to show itself as a trustworthy actor.

Thing is, there are some countries where getting a Global Title could be extremely easy, so instead of giving them to a telecom with millions of mobile or landline subscribers, they might give one to an aggregator, a third party that uses other companies to route their traffic.

This is how these rogue companies got access to the SS7 networks, and allows them to inject millions of messages into other companies’ networks without getting charged at all.

Other techniques involved sending messages through another aggregators and carriers, “jumping” between different networks before reaching the final destination, this would make it more difficult for the carriers to detect the illegal traffic, but it also meant a bigger delay in the reception of the text messages (or perhaps not being received at all).

Carriers Are Taking Actions

Consumers are complaining every day because they are getting unsolicited messages, and costs for the carriers are getting higher because of the tons of SPAM injected on a daily basis.

But nowadays, it is becoming really difficult for grey routes to assure some kind of reliability in terms of getting the messages to their destination. Carriers are being affected by routing billions of messages without getting a penny in response, so they are getting more and more clever in their automatic ways of detecting and blocking rogue traffic.

Technologies like SMS firewalls, heuristic algorithms that can analyze thousands of messages per second, and even teams of auditors go through tons of messages every day, banning gray routes along the way.

Final Words: There’s No Such Thing As A Free Lunch

Of course it can be very tempting to choose a lower price per message by using a rogue provider that offers grey routes, but as you may already know there’s no such thing as a free lunch.

A grey route will end up being blocked in the end (if it’s not blocked already) by the different Carriers but you will get charged nevertheless, and of course you will be paying for nothing in return (no customers will actually get your messages).

The side effect of all of this is of course the increase in the SMS costs, because the carriers are now getting a piece of the action. On the other hand, customers will react better because there will be less SPAM every day annoying them.

Grey routes will be wiped out of the equation soon (they are already nonexistent in countries like Spain and Ukraine), so relying on them will provide more harm than good for your company.

For these reasons it is really important to choose a provider that can reliably reach the customers and can always respond in a timely manner with a great customer support when messages are not getting through.

— The PortaText Team.