Sending Email from an Ubuntu VM on Oracle Cloud (OCI)
A Postfix and OCI Email Delivery setup guide covering SMTP auth, sender approval, SPF/DKIM/DMARC, and the errors that block delivery.
Tag: networking
Debugging an IP camera's RTSP live stream URL
Most IP cameras advertise RTSP support without documenting a working stream URL, and this walks through finding one with ffmpeg, nmap, and the vendor web UI.
An SSH SOCKS5 proxy that stops DNS leaks
An SSH dynamic port forward (ssh -D) turns a remote server into a SOCKS5 proxy so DNS resolution happens remotely, which matters when DoH is blocked by policy.
Why macOS ignores your manual DNS settings
On a managed MacBook, iCloud Private Relay and MDM scoped resolvers silently override manual DNS settings, and scutil --dns shows you which one is winning.
OpenSSH on WSL: enabling remote SSH access on Windows 10
Install and configure OpenSSH inside WSL2, enable systemd, and forward a Windows port so you can SSH into your WSL environment from anywhere on your LAN.
localhost vs 127.0.0.1 vs 0.0.0.0: Network Binding Explained
Why localhost, 127.0.0.1, 0.0.0.0, and * behave differently for MySQL clients and services, and how to find and fix a local port conflict between Docker and SSH.
Migrating a GCP Classic Load Balancer to Global External
GCP lets you migrate a Classic Application Load Balancer to the Global External Load Balancer with a staged, four-state rollout that avoids downtime.
Troubleshooting pgpool Connection Termination in Kubernetes
Intermittent pgpool connection drops in Kubernetes usually trace to max_connections, idle timeouts, or NetworkPolicy issues, found layer by layer.
GKE's Two Health Check Systems and the Premature 502
GKE deployments can pass every readiness probe and still serve 502s, because Kubernetes probes and the Cloud Load Balancer run two separate health checks.
Enabling Gzip and Brotli Compression on Google Cloud CDN
Google Cloud CDN can compress responses with Brotli or Gzip automatically, covering the compressionMode setting, cache invalidation, and verifying it works.
Xiaomi "No Signal": Dialer Codes to ADB Logs
How to debug a "No Signal" or "No SIM" error on a Xiaomi phone, from dialer diagnostic codes through ADB logcat filters to EFS partition failures.
React Dev Proxy Options: package.json vs http-proxy-middleware
Two ways to avoid CORS errors in local React development: the package.json proxy field for one backend, or http-proxy-middleware for several.
Detecting Cloudflare Zero Trust Beyond the WARP Flag
WARP can report itself as off while Zero Trust still routes your Mac's traffic; here is how to check DNS, ASN, and DoH to find out for sure.
Monitor Cloudflare WARP Status on macOS with launchd
A launchd-scheduled shell script that detects when Cloudflare WARP reconnects on a company-managed Mac and sends a desktop notification.
OpenVPN: Restrict Client Access to Specific IPs Only
How to restrict OpenVPN clients to a limited set of destination IPs, using client-config-dir routes, a client-connect script, and iptables rules.
Defending Against DoS Attacks
How to defend against DoS and DDoS attacks with request throttling, input validation, firewall rules, load balancers, and cloud-based mitigation.
域名解析服务探究与nslookup工具使用指南
在互联网世界中，域名解析是一项基础服务，它将用户友好的域名转换为机器可识别的IP地址。本文将介绍如何使用nslookup工具来查找提供域名解析服务的实体。
Linux下实现路由功能
Linux 下的路由配置：静态路由与动态路由的区别，以及用 route 命令管理内核路由表的选项、示例和输出字段说明。
NETSCREEN 5GT密码破解方法
恢复 NetScreen 5GT 密码的两种方法：通过 Console 输入序列号初始化，或用重置针孔硬复位，以及导入旧配置文件前的编辑注意事项。