家庭网络异常与路由转发、数据包加密及VPN防护相关技术咨询

Hey there, let's walk through your network issues and questions step by step—this stuff can feel overwhelming, but we'll break it down clearly:

First, let's address your current network anomalies #

• Snort scan alerts from your router: The enabled UPnP (without access to disable it) is a big red flag here. UPnP is designed to auto-forward ports and add routes for devices, but it's notoriously prone to abuse. Even if you didn't initiate connections, malicious devices on your local network or external actors could exploit UPnP to inject weird routes, or your router might be compromised and running scans on its own. Those Snort alerts are a good sign your tooling is working, but we need to mitigate the root cause.
• Mysterious IP route: Chances are this route was added automatically via UPnP. Since you don't have the router admin password, you can try using the upnpc command-line utility (part of the miniupnpc suite) to list and delete unauthorized UPnP routes. Most consumer routers support the UPnP IGD standard required for this tool. Run upnpc -l to list all active UPnP port mappings/routes, then use upnpc -d <external-port> <protocol> to remove suspicious entries.
• Packet loss: This is likely tied to the weird route or router instability from the scans. Run traceroute <target-ip> (or tracert <target-ip> on Windows) to trace your packet path—if the loss starts right after that mysterious route, that's your culprit. If you can somehow access your router's system logs (even without admin rights, some models let you view basic logs), check for high CPU/memory usage which could also cause packet drops.

Your core questions answered #

• Can I write a script to encrypt packet sends?
  Technically, yes—but it's not practical for most real-world use cases. Writing a secure packet encryption script requires implementing robust encryption algorithms (like AES or RSA), handling key exchange safely, and properly encapsulating encrypted data so it travels across the network correctly. Even small mistakes in implementation can create huge security holes (like hardcoding keys or using weak cipher modes). Instead of building something custom, use established protocols like TLS (for application-level traffic) or IPsec (for network-level encryption)—these are battle-tested and way more reliable.
• Is a VPN a safe way to protect from sniffers?
  Absolutely, when used correctly. A reputable VPN creates an encrypted tunnel between your device and the VPN server, so any sniffer (on your local network or the wider internet) can only see scrambled, unreadable data. But a few key caveats:
  • Stick to well-reviewed VPN providers with a strict no-logs policy—avoid fly-by-night services that might record your traffic.
  • Use modern, secure protocols like WireGuard or OpenVPN (avoid outdated ones like PPTP, which are easily cracked).
  • Remember: A VPN protects your traffic from external sniffers, but if your router is already compromised (e.g., running unauthorized scans), it might still interfere with your connection before it hits the VPN. So addressing the router/UPnP issue should still be a priority if possible.

备注：内容来源于stack exchange，提问作者Tekomo Nakama