V2Ray processes DNS queries sequentially per connection in some modes. A slow DNS server causes queue buildup, leading to context deadline exceeded errors and failed connections.
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.
A slow DNS server can cause several issues, including: v2ray slow dns server
Users can define one or more DNS servers. Common choices:
| Metric | Value | |--------|-------| | Average page load time | 1.2 s | | DNS lookup time | 12 ms | | V2Ray CPU usage | 8% | V2Ray processes DNS queries sequentially per connection in
queryStrategy controls whether V2Ray queries IPv4, IPv6, or both. If you request both (UseIP), but your IPv6 path is broken, the resolver will wait for an IPv6 timeout (~5–10 seconds) before falling back to IPv4.
In restrictive regions, ISPs inject fake replies or reset UDP DNS packets. V2Ray may fall back to TCP, adding latency. "dns": "queryStrategy": "UseIPv4"
"dns":
"queryStrategy": "UseIPv4"
This prevents waiting for AAAA record timeouts.