diff --git a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/authenticator/JavaNetAuthenticator.kt b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/authenticator/JavaNetAuthenticator.kt
index e31b6afc4798..0330e5d043fc 100644
--- a/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/authenticator/JavaNetAuthenticator.kt
+++ b/okhttp/src/commonJvmAndroid/kotlin/okhttp3/internal/authenticator/JavaNetAuthenticator.kt
@@ -53,17 +53,21 @@ class JavaNetAuthenticator(
       val dns = route?.address?.dns ?: defaultDns
       val auth =
         if (proxyAuthorization) {
-          val proxyAddress = proxy.address() as InetSocketAddress
-          Authenticator.requestPasswordAuthentication(
-            proxyAddress.hostName,
-            proxy.connectToInetAddress(url, dns),
-            proxyAddress.port,
-            url.scheme,
-            challenge.realm,
-            challenge.scheme,
-            url.toUrl(),
-            Authenticator.RequestorType.PROXY,
-          )
+          if (proxy.type() == Proxy.Type.HTTP) {
+            val proxyAddress = proxy.address() as InetSocketAddress
+            Authenticator.requestPasswordAuthentication(
+              proxyAddress.hostName,
+              proxy.connectToInetAddress(url, dns),
+              proxyAddress.port,
+              url.scheme,
+              challenge.realm,
+              challenge.scheme,
+              url.toUrl(),
+              Authenticator.RequestorType.PROXY,
+            )
+          } else {
+            null
+          }
         } else {
           Authenticator.requestPasswordAuthentication(
             url.host,
@@ -102,6 +106,13 @@ class JavaNetAuthenticator(
   ): InetAddress =
     when (type()) {
       Proxy.Type.DIRECT -> dns.lookup(url.host).first()
-      else -> (address() as InetSocketAddress).address
+      else -> {
+        val socketAddress = address() as InetSocketAddress
+        if (socketAddress.isUnresolved) {
+          dns.lookup(socketAddress.hostString).first()
+        } else {
+          socketAddress.address
+        }
+      }
     }
 }
diff --git a/okhttp/src/jvmTest/kotlin/okhttp3/internal/authenticator/JavaNetAuthenticatorTest.kt b/okhttp/src/jvmTest/kotlin/okhttp3/internal/authenticator/JavaNetAuthenticatorTest.kt
index bbf4ecf74be2..e0ae707ecaff 100644
--- a/okhttp/src/jvmTest/kotlin/okhttp3/internal/authenticator/JavaNetAuthenticatorTest.kt
+++ b/okhttp/src/jvmTest/kotlin/okhttp3/internal/authenticator/JavaNetAuthenticatorTest.kt
@@ -17,7 +17,8 @@ package okhttp3.internal.authenticator
 
 import java.net.Authenticator
 import java.net.InetAddress
-import junit.framework.TestCase.assertNull
+import java.net.InetSocketAddress
+import java.net.Proxy
 import okhttp3.FakeDns
 import okhttp3.Protocol.HTTP_2
 import okhttp3.Request
@@ -26,6 +27,7 @@ import okhttp3.TestValueFactory
 import okhttp3.internal.RecordingAuthenticator
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNull
 import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.Test
 
@@ -100,4 +102,60 @@ class JavaNetAuthenticatorTest {
     val authRequest = authenticator.authenticate(null, response)
     assertNull(authRequest)
   }
+
+  @Test
+  fun testProxyAuthDirect() {
+    fakeDns["server"] = listOf(InetAddress.getLocalHost())
+
+    val route = factory.newRoute()
+
+    val request =
+      Request
+        .Builder()
+        .url("https://server/robots.txt")
+        .build()
+    val response =
+      Response
+        .Builder()
+        .request(request)
+        .code(407)
+        .header("Proxy-Authenticate", "Basic realm=\"User Visible Realm\"")
+        .protocol(HTTP_2)
+        .message("Unauthorized")
+        .build()
+    val authRequest = authenticator.authenticate(route, response)
+
+    assertNull(authRequest)
+  }
+
+  @Test
+  fun testProxyAuthUnresolvedAddress() {
+    fakeDns["server"] = listOf(InetAddress.getLocalHost())
+    fakeDns["127.0.0.1"] = listOf(InetAddress.getLocalHost())
+
+    // ProxySelector's default implementation, sun.net.spi.DefaultProxySelector, returns unresolved addresses
+    val proxy = Proxy(Proxy.Type.HTTP, InetSocketAddress.createUnresolved("127.0.0.1", 3128))
+    val route = factory.newRoute(proxy = proxy)
+
+    val request =
+      Request
+        .Builder()
+        .url("https://server/robots.txt")
+        .build()
+    val response =
+      Response
+        .Builder()
+        .request(request)
+        .code(407)
+        .header("Proxy-Authenticate", "Basic realm=\"User Visible Realm\"")
+        .protocol(HTTP_2)
+        .message("Unauthorized")
+        .build()
+    val authRequest = authenticator.authenticate(route, response)
+
+    assertEquals(
+      "Basic ${RecordingAuthenticator.BASE_64_CREDENTIALS}",
+      authRequest!!.header("Proxy-Authorization"),
+    )
+  }
 }