From f67ebac581e05067833491f0bb1672651237e876 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Raynaud?=
 <30211659+carlodrift@users.noreply.github.com>
Date: Sun, 28 Jun 2026 19:49:00 +0200
Subject: [PATCH 1/2] Use a bounded thread pool for backend DNS resolution

---
 .../netty/SeparatePoolInetNameResolver.java        | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/proxy/src/main/java/com/velocitypowered/proxy/network/netty/SeparatePoolInetNameResolver.java b/proxy/src/main/java/com/velocitypowered/proxy/network/netty/SeparatePoolInetNameResolver.java
index 5fc309ae9a..8d0bee291a 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/network/netty/SeparatePoolInetNameResolver.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/network/netty/SeparatePoolInetNameResolver.java
@@ -32,17 +32,20 @@
 import java.net.InetSocketAddress;
 import java.util.List;
 import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
 import java.util.concurrent.RejectedExecutionException;
+import java.util.concurrent.SynchronousQueue;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
 /**
  * An implementation of {@code InetNameResolver} that performs blocking DNS name lookups
- * in a separate thread, avoiding blocking the Netty threads for an extended period of time
- * and without the downsides of Netty's native DNS resolver.
+ * on a small bounded pool of separate threads, avoiding blocking the Netty threads for an
+ * extended period of time and without the downsides of Netty's native DNS resolver.
  */
 public final class SeparatePoolInetNameResolver extends InetNameResolver {
 
+  private static final int MAX_RESOLVE_THREADS = 8;
+
   private final ExecutorService resolveExecutor;
   private final InetNameResolver delegate;
   private final Cache<String, List<InetAddress>> cache;
@@ -56,9 +59,10 @@ public final class SeparatePoolInetNameResolver extends InetNameResolver {
    */
   public SeparatePoolInetNameResolver(EventExecutor executor) {
     super(executor);
-    this.resolveExecutor = Executors.newSingleThreadExecutor(
+    this.resolveExecutor = new ThreadPoolExecutor(0, MAX_RESOLVE_THREADS,
+        60L, TimeUnit.SECONDS, new SynchronousQueue<>(),
         new ThreadFactoryBuilder()
-            .setNameFormat("Velocity DNS Resolver")
+            .setNameFormat("Velocity DNS Resolver #%d")
             .setDaemon(true)
             .build());
     this.delegate = new DefaultNameResolver(executor);

From 5aa2a3f524c261afb93dbe8afbb7214303875c7c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Raynaud?=
 <30211659+carlodrift@users.noreply.github.com>
Date: Tue, 7 Jul 2026 23:25:19 +0200
Subject: [PATCH 2/2] Queue DNS lookups instead of rejecting when the resolver
 pool is busy

---
 .../network/netty/SeparatePoolInetNameResolver.java      | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/proxy/src/main/java/com/velocitypowered/proxy/network/netty/SeparatePoolInetNameResolver.java b/proxy/src/main/java/com/velocitypowered/proxy/network/netty/SeparatePoolInetNameResolver.java
index 8d0bee291a..fe5e8b29dd 100644
--- a/proxy/src/main/java/com/velocitypowered/proxy/network/netty/SeparatePoolInetNameResolver.java
+++ b/proxy/src/main/java/com/velocitypowered/proxy/network/netty/SeparatePoolInetNameResolver.java
@@ -32,8 +32,8 @@
 import java.net.InetSocketAddress;
 import java.util.List;
 import java.util.concurrent.ExecutorService;
+import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.RejectedExecutionException;
-import java.util.concurrent.SynchronousQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
@@ -59,12 +59,15 @@ public final class SeparatePoolInetNameResolver extends InetNameResolver {
    */
   public SeparatePoolInetNameResolver(EventExecutor executor) {
     super(executor);
-    this.resolveExecutor = new ThreadPoolExecutor(0, MAX_RESOLVE_THREADS,
-        60L, TimeUnit.SECONDS, new SynchronousQueue<>(),
+    ThreadPoolExecutor resolveExecutor = new ThreadPoolExecutor(
+        MAX_RESOLVE_THREADS, MAX_RESOLVE_THREADS,
+        60L, TimeUnit.SECONDS, new LinkedBlockingQueue<>(),
         new ThreadFactoryBuilder()
             .setNameFormat("Velocity DNS Resolver #%d")
             .setDaemon(true)
             .build());
+    resolveExecutor.allowCoreThreadTimeOut(true);
+    this.resolveExecutor = resolveExecutor;
     this.delegate = new DefaultNameResolver(executor);
     this.cache = Caffeine.newBuilder()
         .expireAfterWrite(30, TimeUnit.SECONDS)