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How to Use IPv6 Proxies with SOCKS5 and SOCKS5H

Updated

When using an IPv6 proxy with the SOCKS5 protocol, you may occasionally encounter connection issues due to how DNS resolution is handled. This guide explains how to properly configure SOCKS5 connections and how to fix the most common problem using SOCKS5H.

When Should You Use SOCKS5H Instead of SOCKS5?

In IPv6 environments, the operating system might not resolve domain names to IPv6 addresses by default. This causes issues when connecting via SOCKS5 using a domain (like cheaper-pong.proxycheap.io). If DNS resolution fails locally, the connection will break even if the proxy is valid.

🔧 Recommended Setup (with curl)

❌ Failing Example (due to local DNS resolution):

curl -6 -x socks5://user:password@1.2.3.4:12345 http://cheaper-pong.proxycheap.io

 

🛠️ Working Example (uses proxy DNS via socks5h):

curl -6 -x socks5h://user:password@1.2.3.4:12345 http://cheaper-pong.proxycheap.io

 

You will get a valid JSON response showing your IPv6 IP and source node, like this:

{
  "ip": "2001:0db8:85a3:0000:0000:8a2e:0370:7334",
  "src": "eu4"
}
 

Common Mistakes

  • ❌ Trying to connect to an IPv4 address using an IPv6 proxy (this will fail).

  • ❌ Using socks5:// instead of socks5h:// when the destination is a domain.

  • ✅ Use socks5h:// with domain names and IPv6 proxies.

Check out following article for further guidance and help:

How can I test if my SOCKS5 IPv6 proxy is working correctly?

Can I use IPv4 destination addresses with an IPv6-only proxy?

What is the difference between SOCKS5 and SOCKS5H?

How to Check if a Website Supports IPv6?

 
 

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