Network Protocols
TCP/IP, DNS, HTTP, TLS, BGP, OSPF and the protocols the internet runs on.
Network Protocols articles
RTP and RTCP Basics for Troubleshooting Voice
SIP sets the call up; RTP carries the audio. When a call sounds bad, RTP sequence gaps, jitter, and RTCP receiver reports are where the answer is.
October 24, 2026LDAP Search Filters You Actually Need
LDAP's prefix-notation filter syntax looks alien for five minutes, then becomes second nature. Here are the filters that answer real questions.
October 24, 2026DNS Resolution, Step by Step
The recursion from root to authoritative, why TTLs matter, and the dig commands that show you exactly where a lookup goes wrong.
October 24, 2026OSPF Areas and LSA Types, Explained
OSPF scales by splitting a domain into areas and limiting what routing information crosses the boundary. Here's what each LSA type carries and why stub areas exist.
October 24, 2026HTTP/1.1 vs HTTP/2 vs HTTP/3, in Practice
What actually changed between the three HTTP versions, where each still bites you, and how to check what your server negotiates.
October 24, 2026ICMP Beyond Ping: The Messages That Keep IP Working
ICMP is not just ping. The control messages that make PMTUD, traceroute, and error reporting work — and why a blanket ICMP block causes weird hangs.
October 24, 2026SIP Registration and INVITE Flow, Step by Step
Follow a SIP call from the phone booting up to media flowing: REGISTER, the INVITE three-way handshake, and the headers that decide where responses and RTP go.
October 24, 2026MQTT QoS Levels Explained
QoS 1 can deliver twice, QoS 2 never does but costs four packets, QoS 0 might not deliver at all. Here's the flow behind each and when to use it.
October 24, 2026What Happens When You Type a URL and Press Enter
Every layer a request passes through, from DNS to first paint, and how to watch each one from the command line.
October 24, 2026ARP and the Neighbour Table, Explained
ARP resolves IP to MAC on the local link. How the cache works, why gratuitous ARP matters for failover, and the commands to inspect and flush it.
October 24, 2026FTP Active vs Passive, and Why SFTP Won
FTP's separate control and data connections made it a firewall nightmare. Here's active vs passive, and why SFTP — a totally different protocol — replaced it.
October 24, 2026SMB Versions and Signing, Demystified
SMB1 is a security liability, SMB3 encrypts and signs. Here's how dialect negotiation works and how to tell which one a connection actually used.
October 24, 2026