关于 traceroute 结果中出现私有IP地址的技术疑问

Hey there! Let's unpack your networking questions step by step—this is a super common confusion when you're just getting started, so no need to feel stuck!

为什么 traceroute 里会出现私有IP？ #

Great question! You're right that private IP ranges (like 10.x.x.x, 192.168.x.x, 172.16-31.x.x) aren't routable across the public internet—but they are widely used inside private networks, including your internet service provider's (ISP) internal infrastructure.

Those 10.x.x.x hops you see are routers inside your mobile carrier's private network. ISPs use private IPs to build their internal backbone and manage traffic between their cell towers, regional hubs, and the public internet. These addresses never leave the ISP's network, so they don't conflict with public IPs elsewhere.

为什么前几跳和中间有些跳是空的？ #

Traceroute relies on receiving ICMP "time exceeded" packets from each router along the path to map the route. When a hop shows up as empty, it usually means one of two things:

• The router at that hop is configured to ignore ICMP traceroute requests (many network admins disable this for security or performance reasons)
• The device is part of a network segment that doesn't forward or respond to these diagnostic packets (common in mobile carrier networks for their core infrastructure)

For your iPhone's trace, the first 5 empty hops are likely the cell tower and carrier gateway devices connecting your phone to their network—these often don't respond to traceroute. The empty hops later on are just more of the same: routers that don't send back the required ICMP response.

为什么你的 192.0.0.2 不在 hop 1？ #

On mobile networks, your phone's 192.0.0.2 is a private IP assigned by the carrier for internal use within their network. Traceroute doesn't typically show your own device's IP as the first hop—it starts tracking from the first gateway your traffic hits after leaving your device. Since that first gateway (part of the carrier's network) isn't responding to traceroute, you see an empty hop instead.

为什么 Security Trails 无法做反向查询？ #

Reverse DNS lookups (which tools like Security Trails use) only work for public IP addresses that have been registered and assigned DNS records. Private IP ranges have no public DNS entries at all—they're meant for internal use only. Even some public IPs (like certain ISP nodes) might not have reverse DNS configured, so you won't get results for those either.

备注：内容来源于stack exchange，提问作者joncavaz