diff --git a/proxy/src/main/java/google/registry/proxy/ProxyModule.java b/proxy/src/main/java/google/registry/proxy/ProxyModule.java
index 8bc02a7c7..361ea866d 100644
--- a/proxy/src/main/java/google/registry/proxy/ProxyModule.java
+++ b/proxy/src/main/java/google/registry/proxy/ProxyModule.java
@@ -25,8 +25,6 @@ import com.google.api.services.cloudkms.v1.model.DecryptRequest;
 import com.google.api.services.storage.Storage;
 import com.google.auth.oauth2.AccessToken;
 import com.google.auth.oauth2.GoogleCredentials;
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Maps;
 import com.google.common.flogger.LoggerConfig;
 import com.google.monitoring.metrics.MetricReporter;
 import dagger.Component;
@@ -185,12 +183,6 @@ public class ProxyModule {
     return Optional.ofNullable(httpsWhoisPort).orElse(config.webWhois.httpsPort);
   }
 
-  @Provides
-  ImmutableMap<Integer, FrontendProtocol> providePortToProtocolMap(
-      Set<FrontendProtocol> protocolSet) {
-    return Maps.uniqueIndex(protocolSet, Protocol::port);
-  }
-
   @Provides
   Environment provideEnvironment() {
     return env;
@@ -359,7 +351,7 @@ public class ProxyModule {
       })
   interface ProxyComponent {
 
-    ImmutableMap<Integer, FrontendProtocol> portToProtocolMap();
+    Set<FrontendProtocol> protocols();
 
     MetricReporter metricReporter();
   }
diff --git a/proxy/src/main/java/google/registry/proxy/ProxyServer.java b/proxy/src/main/java/google/registry/proxy/ProxyServer.java
index 03613992a..0df563443 100644
--- a/proxy/src/main/java/google/registry/proxy/ProxyServer.java
+++ b/proxy/src/main/java/google/registry/proxy/ProxyServer.java
@@ -20,7 +20,7 @@ import static google.registry.proxy.handler.RelayHandler.RELAY_CHANNEL_KEY;
 import static google.registry.proxy.handler.RelayHandler.writeToRelayChannel;
 
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.flogger.FluentLogger;
 import com.google.monitoring.metrics.MetricReporter;
 import google.registry.proxy.Protocol.BackendProtocol;
@@ -51,28 +51,27 @@ import java.util.concurrent.TimeoutException;
 import javax.inject.Provider;
 
 /**
- * A multi-protocol proxy server that listens on port(s) specified in {@link
- * ProxyModule.ProxyComponent#portToProtocolMap()} }.
+ * A multi-protocol proxy server that listens for protocols in {@link
+ * ProxyModule.ProxyComponent#protocols()} }.
  */
 public class ProxyServer implements Runnable {
-
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
   /** Maximum length of the queue of incoming connections. */
   private static final int MAX_SOCKET_BACKLOG = 128;
 
-  private final ImmutableMap<Integer, FrontendProtocol> portToProtocolMap;
+  private final ImmutableSet<FrontendProtocol> protocols;
   private final HashMap<Integer, Channel> portToChannelMap = new HashMap<>();
   private final EventLoopGroup eventGroup = new NioEventLoopGroup();
 
   ProxyServer(ProxyComponent proxyComponent) {
-    this.portToProtocolMap = proxyComponent.portToProtocolMap();
+    this.protocols = ImmutableSet.copyOf(proxyComponent.protocols());
   }
 
   /**
    * A {@link ChannelInitializer} for connections from a client of a certain protocol.
    *
-   * <p>The {@link #initChannel} method does the following:
+   * <p>The {@link #initChannel(NioSocketChannel)} method does the following:
    *
    * <ol>
    *   <li>Determine the {@link FrontendProtocol} of the inbound {@link Channel} from its parent
@@ -263,8 +262,9 @@ public class ProxyServer implements Runnable {
               .childOption(ChannelOption.AUTO_READ, false);
 
       // Bind to each port specified in portToHandlersMap.
-      portToProtocolMap.forEach(
-          (port, protocol) -> {
+      protocols.forEach(
+          protocol -> {
+            int port = protocol.port();
             try {
               // Wait for binding to be established for each listening port.
               ChannelFuture serverChannelFuture = serverBootstrap.bind(port).sync();