ure encryption and authentication but not always enabled, or only enabled for a portion of the traffic, driven by compute resource limitations or the false assumption that the equipment is connected to a secure network. VPN support also applies to associated networking equipment such as front haul and cell site routing equipment which should include secure configuration and services. Firewalls protect network services by only allowing specific connections and blocking malicious traffic. It is vital that firewalls are configured carefully, as a misconfiguration could allow bypassing the access control mechanisms. ACLs are a network filter utilized by routers and some switches to permit and restrict data flows into and out of network interfaces. When an ACL is configured on an interface, the network device analyzes data passing through the interface, compares it to the criteria described in the ACL, and either permits the data to flow or prohibits it. Attackers are sometimes able to circumvent firewalls, for example, by splitting Transmission Control Protocol (TCP) packets in such a way their header does not fit into one IP packet, by using specific network source ports or by using specific TCP flags. These configuration errors might lead to more services being accessible than desired. The network layout is important when it comes to security. All hosts must be assigned to the correct zones. For example, if an externally accessible web server is in the same zone as the internal servers, this is a major risk. If the web server has a vulnerability, this can have consequences for the entire internal infrastructure. Chapter 5 System software It is important that proper security decisions are made during the network planning phase. Consider the use of virtual local area networks (VLANs) and subnets to isolate traffic domains. Access to the network may be done by means outside of the 4G/5G network itself. Consider a parallel operated Wi-Fi network with common equipment for Edge Computing. Companies often set up a separat