ngrok Alternatives: Free and Self-Hosted Ways to Expose Localhost
Share a local web server or receive webhooks: Cloudflare Tunnel, Tailscale Funnel, localtunnel, SSH reverse tunnels, frp, zrok and self-hosting.
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Networking
DNS, reverse proxies, bandwidth, routing and network performance.
iperf3: Measure Real Network Throughput Between Servers
Test bandwidth between two machines with iperf3: server and client mode, TCP and UDP tests, parallel streams, reverse direction, and interpreting the results.
dig Command: Query and Troubleshoot DNS Like a Pro
Use dig to look up A, AAAA, MX, TXT, NS and CNAME records, query specific resolvers, trace delegation, check propagation, reverse DNS and DNSSEC.
iftop and nethogs: See Live Bandwidth per Connection and Process
See what is using your bandwidth right now: iftop shows traffic per remote host and port, nethogs per process, plus nload, bmon and what to do next.
ZeroTier on a VPS: Create a Private Network Across Devices
Connect servers, laptops and home devices into one private network with ZeroTier: create a network, join, authorise members, routing and flow rules.
Enable TCP BBR on Linux: Faster Throughput Over Long Distances
How TCP congestion control works, BBR vs CUBIC, enabling BBR with fq on Ubuntu, Debian and RHEL, verifying it, measuring the effect, when it helps.
Reduce Latency for Users in China: Server Location and Routing
Why sites hosted abroad are slow in mainland China and how to fix it: server location and routes, blocked third-party resources, fewer round trips, BBR.
DNS over HTTPS and DNS over TLS on Linux Servers
Encrypt DNS with DoT or DoH: how they differ from plain DNS, DoT in systemd-resolved, a local DoH proxy, Unbound, Pi-hole or AdGuard upstreams, trade-offs.
How to Change DNS Servers on Linux (resolved, Netplan, nmcli)
Change DNS resolvers on Ubuntu, Debian and RHEL: systemd-resolved, Netplan, NetworkManager and resolv.conf, and check which resolver is used.
Set Up an OpenVPN Server on Ubuntu or Debian
Install an OpenVPN server on a VPS with Easy-RSA certificates, routing and NAT, create client profiles for any device, and revoke access.
QUIC Protocol Explained: The UDP Transport Behind HTTP/3
How QUIC works: streams without head-of-line blocking, built-in TLS 1.3, 0-RTT, connection migration, firewall and load balancer considerations, debugging.
Nginx Reverse Proxy for Multiple Docker Containers (with HTTPS)
Serve several Docker apps on one VPS under different domains: localhost-only ports, Nginx server blocks, Let’s Encrypt, WebSockets, Caddy.
Unbound DNS Resolver: Run Your Own Recursive DNS on a VPS
Run Unbound as a private recursive, validating resolver: access control, DNSSEC, caching and prefetch, DoT upstreams, Pi-hole, and no open resolver.
Singapore vs Hong Kong Servers for Southeast Asia
Singapore or Hong Kong for Southeast Asian users? Latency by country, China connectivity, routing quirks, and how to test before you choose.
Dynamic DNS (DDNS): Keep a Hostname Pointed at a Changing IP
Dynamic DNS for home servers: when you need it, free DDNS services, updating Cloudflare DNS with a script or ddclient, IPv6, and when a VPS is better.
Nameservers Explained: Change Nameservers and Move DNS Hosting
What nameservers do, registrar vs DNS host, delegation and glue records, moving DNS to Cloudflare or another provider safely, and troubleshooting.
Add a Secondary IP Address on Linux (Netplan, ifupdown, nmcli)
Add extra IPv4 addresses to a Linux server: temporary with ip addr, permanent with Netplan, ifupdown or nmcli, then use them in Nginx, mail and outbound.
Hong Kong VPS for China Traffic: Why CN2 + BGP Matters
Why ordinary routes to mainland China slow down at peak hours, what CN2 GT and CN2 GIA are, and how to test a Hong Kong VPS route.
OpenVPN vs WireGuard: Which VPN Should You Run on Your VPS?
OpenVPN vs WireGuard for a self-hosted VPN: speed and CPU, setup effort, security design, TCP 443 for restrictive networks, user management, which to pick.
VPS Bandwidth Explained: Port Speed, Transfer, Unmetered
Port speed vs monthly transfer vs unmetered bandwidth: what VPS bandwidth numbers mean, how much you need, and why real speed varies.
keepalived and VRRP: Floating IP Failover for Load Balancers
Make Nginx or HAProxy highly available with keepalived: VRRP and a virtual IP, MASTER/BACKUP config, health checks, unicast peers, and failover tests.
Traffic Shaping on Linux with tc: Limit Bandwidth and Add Latency
Shape traffic with Linux tc: limit bandwidth per interface or IP with HTB, fair queuing with fq_codel, ingress policing, and netem for latency and loss.
ip Command in Linux: Addresses, Routes and Interfaces
Use the ip command to show and configure IP addresses, interfaces, routes and neighbours on Linux, with ifconfig and route equivalents and persistence tips.
PTR Records and Reverse DNS: Why Mail Servers Need Them
What reverse DNS (PTR) records are, why email deliverability depends on them, forward-confirmed rDNS, setting PTR for your IP, and checking it.