diff --git a/easytier/src/common/global_ctx.rs b/easytier/src/common/global_ctx.rs
index 4bc1e700..46af1d8d 100644
--- a/easytier/src/common/global_ctx.rs
+++ b/easytier/src/common/global_ctx.rs
@@ -5,7 +5,7 @@ use hmac::{Hmac, Mac};
use sha2::Sha256;
use socket2::Protocol;
use std::{
- collections::{HashMap, hash_map::DefaultHasher},
+ collections::{BTreeSet, HashMap, hash_map::DefaultHasher},
hash::Hasher,
iter,
net::{IpAddr, SocketAddr},
@@ -207,6 +207,7 @@ pub struct GlobalCtx {
cached_ipv4: AtomicCell