Unfortunately, there are also errors that have been designed into the system on purpose. Some manufacturers intending to sell their products abroad have been requested by their respective governments to install so-called backdoors into their equipment. The aim of these governments is at first glance a comprehensible one: Their intend is to prevent that a product, should it fall into wrong hands, to be used against their own interest. Unfortunately, such backdoors in rigged products must always be expected to become public knowledge, or even worse, exclusive knowledge to criminals or other countries state actors. They will take advantage from it, be it financial through ransom demands or ideological through cyber warfare.
So how can you make sure, that you can trust your equipment? Not all manufactures can be forced to include such backdoors - the legal system at their residence prevents it. Choose a manufacture with an ownership and management with no politically agenda. Last but not least, choose one that allows you to verify their claims of security.
Securosys designs and manufactures its network security equipment in Switzerland. No backdoors have been added to its products. Even more, Securosys equipment is active from the moment it is shipped to the customer. It will inform the customer if it has been tampered with during transport or storage.