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nftables Hairpin NAT: Fix NAT Loopback When Your Public IP Fails from the LAN Your port forwarding works perfectly from the Internet. A remote client can connect to: https://203.0.113.10 and nftables forwards the connection to: 192.168.20.10 But a workstation inside…
nftables DNAT Port Forwarding Not Working: Complete Linux Troubleshooting Guide You created the DNAT rule. The public port is correct. The internal server is running. Yet the connection still times out. This is one of the most frustrating Linux firewall…
Linux DMZ with nftables: Build a Secure VLAN, NAT and Stateful Firewall Architecture A DMZ is one of the most important network-security patterns to understand when turning a Linux system into a real router or firewall. The basic idea is…
nftables Sets and Maps: Build a Scalable Linux Firewall Without Hundreds of Rules A small Linux firewall is easy to understand. You might start with a few rules: tcp dport 22 accept tcp dport 80 accept tcp dport 443 accept…
Linux nftables Inter-VLAN Firewall: Build Stateful Firewall Rules Between VLANs Inter-VLAN routing solves one problem: it allows hosts in different VLANs to communicate. But in a production network, simply making every VLAN reachable from every other VLAN is rarely the…
Linux Inter-VLAN Routing with Network Namespaces: Build a Virtual Router Between VLANs VLANs are excellent for separating devices into independent Layer 2 broadcast domains. But isolation creates another requirement: What happens when devices in different VLANs need to communicate? Consider…
Linux Bridge VLAN Filtering Explained: Build a VLAN-Aware Virtual Switch with Network Namespaces A basic Linux bridge can connect multiple interfaces and forward Ethernet frames between them much like a software Layer 2 switch. But real networks rarely consist of…
Linux Bridge Networking with Network Namespaces and veth: Build a Virtual Layer 2 Network Linux can act as much more than an endpoint on a network. With Linux bridges, network namespaces, and veth pairs, a single Linux host can become…
Linux Network Namespaces Explained: Build Isolated Networks with ip netns and veth Modern Linux networking can do far more than assign IP addresses to physical interfaces. A single Linux machine can host multiple independent network environments, each with its own…
Linux VRF Explained: Build Isolated Routing Tables with iproute2 A Linux server can have multiple network interfaces, multiple gateways, and multiple routing tables. At first, ordinary routing may be enough. As the network grows, you may introduce source-based routing with…