V2ray Slow Dns Server -

A V2Ray Slow DNS server is a specialized VPN configuration used primarily to bypass internet censorship and firewalls by tunneling traffic through the DNS protocol (UDP Port 53)

  "dns": 
    "servers": [
2.2. UDP-based DNS over Congested Networks
Many networks prioritize TCP over UDP, or actively throttle UDP DNS traffic. V2Ray sending DNS via UDP to 8.8.8.8:53 may suffer packet loss and retries. v2ray slow dns server

You type google.com.
V2Ray intercepts the request.
V2Ray queries a DNS server.
V2Ray waits for the IP address.
V2Ray checks routing rules (e.g., "Is this IP in China?").
V2Ray forwards the connection.