/Short VersionIntroductionThe introduction of Ethernet and Gigabit Ethernet  as the main invehicle network infrastructure is the technical foundation for different new functionalities such as piloted driving, minimizing the CO2- footprint and others. The high data rate of such systems influences also the used microcontrollers due the fact that a big amount of data has to be transferred, encrypted, etc.Figure 1Motivation - Vehicles will become connected to uncontrolled networksThe usage of Ethernet as the in-vehicle-network enables the possibility that future road vehicles are going to be connected with other vehicles and information systems to improve system functionality. These previously closed automotive systems will be opened up for external access (see Figure 1). This can be Car2X connectivity or connection to personal devices. Allowing vehicle systems to communicate with other systems that are not within their physical boundaries impose a previously non-existing security problem. Any external communication with the vehicle system must be considered as a potential security threat, which may impact the system functionality or any of the safety properties.This may result in new vulnerabilities that could be exploited by malicious attackers [1, 3]. Any external access to the system must be authorized and firewalled, so that only trustworthy users and services can make use of the functionality.In order to achieve a high level of security a holistic security concept is highly essential. A holistic security concept is based on the following basic building block:Physical Security (tamper proof)Network SecuritySecure System Software (ECU Hardening)Application HardeningIn order to archive a high level of confidence for the internal secure network communication a firewall concept is required. A holistic firewall approach includes firewalls in different ECU with different firewall functionalities.This paper addresses the hardware and software architecture patterns for building automotive firewall systems.In the first chapter state-of-the-art firewall concepts will be shortly presented and afterwards special automotive requirements will be introduced.In following chapters the basic requirements for a firewall system from the OEM point of view will be discussed. It is followed by having a closer look on the hardware aspects which come along with automotive requirements.The paper finishes with some software aspects about realizing firewalls.