Network Protocols
TCP/IP, DNS, HTTP, TLS, BGP, OSPF and the protocols the internet runs on.
Network Protocols articles
IPv6 for People Who Know IPv4
If you know IPv4, IPv6 is mostly 'bigger addresses, no NAT, autoconfiguration, and ARP becomes NDP'. Here's what actually changes day to day.
October 24, 2026802.1Q VLANs Explained
A VLAN is a broadcast domain defined by a 12-bit tag in the frame. Here's access vs trunk ports, the native-VLAN trap, and how Linux does tagged interfaces.
October 24, 2026VXLAN and Overlay Networks
VXLAN wraps L2 frames in UDP so you can stretch a segment across L3. It's the plumbing under Kubernetes CNIs, OpenStack, and VMware NSX — here's how it works.
October 24, 2026TCP Congestion Control Basics
TCP throughput is governed by the congestion window, not just bandwidth. Here's slow start, CUBIC vs BBR, and why a big buffer can make things slower.
October 24, 2026VRRP and keepalived for Gateway/Service Failover
VRRP lets two or more nodes share one virtual IP so a failure is invisible to clients. keepalived is the common Linux implementation — here's a working active/passive VIP.
October 24, 2026DNS over TLS and DNS over HTTPS
Plain DNS is unencrypted and unauthenticated. DoT and DoH fix the transport — here's how each works, and the trade-off between privacy and network visibility.
October 24, 2026WebSocket vs Long Polling vs SSE
Real-time updates in the browser have three transports. WebSocket is bidirectional and cheap per-message; SSE is simpler; long polling still works through hostile proxies.
October 24, 2026NTP: Stratum, Clock Discipline, and Why Time Drifts
What stratum actually indicates, why chrony slews instead of jumping, and how to tell whether a clock problem is the client, the server, or the network.
October 24, 2026BGP for Sysadmins
The parts of BGP a sysadmin needs: AS numbers, path selection, why routes flap, and what RPKI actually protects against.
October 24, 2026The TLS 1.3 Handshake, Walked Through
ClientHello to Finished in one round trip, why 1.3 is faster and safer than 1.2, and how to inspect a live handshake.
October 24, 2026Understanding MTU and Path MTU Discovery
The single most common cause of 'the connection hangs after it connects' — a broken path MTU — and the two ways to fix it.
October 24, 2026SNMP v2c vs v3, in Practice
The SNMP concepts you need to poll a device, why v2c is effectively cleartext, and a working SNMPv3 authPriv config.
October 24, 2026