EC
ErrorKind::HostUnreachable
RustERRORCommonNetwork

Host is unreachable

Quick Answer

Verify routing table, DNS resolution, and firewall rules for the target host.

What this means

No route to the target host exists from this machine.

Why it happens
  1. 1No route in routing table
  2. 2Target IP unreachable from this network segment
  3. 3ICMP unreachable returned by a router

Fix

Validate host before connecting

Validate host before connecting
use std::net::ToSocketAddrs;
let addrs: Vec<_> = "example.com:443".to_socket_addrs()?.collect();
if addrs.is_empty() { return Err("DNS resolution failed".into()); }

Why this works

DNS resolution failure surfaces before a connection attempt wastes time.

Code examples
Noterust
// Added in Rust 1.83; maps to EHOSTUNREACH on Linux
Same error in other languages
EHOSTUNREACHin Linux / POSIX→
Sources

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