Getting Started with Airport Subscriptions: A Guide to Clash Link Formats and Core Security Practices

What is an Airport Subscription Link?

An airport subscription link is a special URL provided by service providers, typically starting with https://, containing Base64-encoded node configuration information. When users import the link into clients like Clash, the client automatically parses and updates the node list, enabling one-click configuration.

Parsing the Clash Subscription Link Format

A typical Clash subscription link looks like this:

https://example.com/sub?token=abc123&flag=clash

• token parameter: Used for authentication, unique per user, must be kept secure.
• flag parameter: Specifies the return format; clash indicates Clash-native YAML configuration.

The server returns a YAML file containing fields such as proxies, proxy-groups, and rules. Each node in the proxies list includes key information:

• name: Node name, e.g., "Hong Kong 01".
• type: Protocol type, common ones include ss (Shadowsocks), vmess, trojan, etc.
• server: Server address (IP or domain).
• port: Port number.
• cipher: Encryption method, e.g., aes-256-gcm.
• password/uuid: Authentication credentials.

Core Security Practices

1. Protect Your Subscription Link

The token in the subscription link is equivalent to your account password. If leaked, others can steal your traffic or even obtain node information. Recommendations:

• Do not share the link on public networks or in screenshots.
• Regularly reset the token in the service provider's backend.
• Avoid storing the subscribe-url in plain text when using Clash.

2. Verify Node Security

Some airports may log user activity. Recommendations:

• Prefer protocols that support obfuscation, such as vmess+ws+tls.
• Avoid using subscription links from unknown sources to prevent man-in-the-middle attacks.
• Regularly check node latency and availability; remove suspicious nodes promptly.

3. Privacy Protection Measures

• When enabling "Global Proxy" or "Rule Mode" in the client, watch out for DNS leaks.
• Configure trusted DNS in Clash's dns field (e.g., https://dns.cloudflare.com/dns-query).
• Avoid exposing your real IP in subscription configurations.

FAQ

Q1: What if my subscription link expires?

First check your network connection, then contact the service provider to confirm if the link has expired. Some airports offer a "one-click update" feature; you can manually refresh in the client.

Q2: How do I import a subscription link into Clash?

In the Clash client, find the "Subscription" or "Profile" option, paste the link, and click "Update". Clash will automatically download and apply the configuration.

Q3: How to troubleshoot slow node speeds?

• Use the client's built-in latency test feature.
• Switch to different nodes or protocols.
• Check your local network environment, such as firewall or ISP restrictions.