关于使用netsh阻止网站及网站IP频繁变更原因的技术咨询

Hey there! Let's break down your questions step by step, since you already have some experience with netsh firewall rules.

一、如何用netsh阻止网站 #

The rule you're using works perfectly for blocking individual IPs, but websites (especially larger ones) typically have multiple IP addresses associated with their domain, and netsh firewall rules don't support directly using domain names—they rely on static IPs. Here's how to make it work:

• Get all IPs for the website
  First, you need to look up every IP linked to the domain. Use commands like nslookup your-target-website.com or tracert your-target-website.com in Command Prompt. For popular sites like Google or Facebook, you'll probably see a list of IPs instead of just one.

• Create a single rule for multiple IPs
  Instead of adding separate rules for each IP, you can list them all in one command using commas. For example, if you found two IPs for the site, the command would look like:

  netsh advfirewall firewall add rule name="Block [Website Name]" dir=out remoteip=192.0.2.1,192.0.2.2 protocol=TCP localport=80,443 action=block
  

  Adding localport=80,443 ensures you're only blocking HTTP and HTTPS traffic to those IPs, so you don't accidentally block other services using the same IPs.

• A heads-up for dynamic IP sites
  If the website's IPs change often (which we'll get to next), this method will require you to update the rule regularly. As an alternative, you can edit your hosts file (located at C:\Windows\System32\drivers\etc\hosts) to map the domain to 127.0.0.1 or 0.0.0.0—this redirects the domain to your local machine, effectively blocking access. It's simpler for sites with shifting IPs, though it's a DNS-level block rather than a firewall rule.

二、为什么网站IP会频繁变更？ #

There are a few common reasons for this, mostly tied to performance, reliability, and security:

• Load Balancing: Big websites use clusters of servers to spread out traffic. When you visit, the site's system assigns you to an available server, which might have a different IP each time. This prevents any single server from getting overwhelmed.
• CDN (Content Delivery Networks): Most popular sites use CDNs like Cloudflare or Akamai. These networks have nodes all over the world, and your request gets routed to the closest node to speed up load times. The IP you see is the CDN node's IP, not the site's actual server IP—and it can change based on your location or network.
• Fault Tolerance: If a server or data center goes down, the site's infrastructure automatically switches traffic to a backup server with a different IP. This keeps the site online without you noticing a thing.
• Dynamic IPs (Smaller Sites): Some smaller websites use dynamic IP addresses from their ISP, which get changed periodically by the provider.
• Security: Sites might rotate IPs to avoid DDoS attacks or other malicious targeting. Changing IPs makes it harder for attackers to focus their efforts on a single address.

备注：内容来源于stack exchange，提问作者mark