diff --git a/main-command/src/main/scala/sbt/BasicKeys.scala b/main-command/src/main/scala/sbt/BasicKeys.scala
index ca77d1d73..d42a1d381 100644
--- a/main-command/src/main/scala/sbt/BasicKeys.scala
+++ b/main-command/src/main/scala/sbt/BasicKeys.scala
@@ -8,6 +8,7 @@ object BasicKeys {
   val historyPath = AttributeKey[Option[File]]("history", "The location where command line history is persisted.", 40)
   val shellPrompt = AttributeKey[State => String]("shell-prompt", "The function that constructs the command prompt from the current build state.", 10000)
   val watch = AttributeKey[Watched]("watch", "Continuous execution configuration.", 1000)
+  val serverPort = AttributeKey[Int]("server-port", "The port number used by server command.", 10000)
   private[sbt] val interactive = AttributeKey[Boolean]("interactive", "True if commands are currently being entered from an interactive environment.", 10)
   private[sbt] val classLoaderCache = AttributeKey[ClassLoaderCache]("class-loader-cache", "Caches class loaders based on the classpath entries and last modified times.", 10)
   private[sbt] val OnFailureStack = AttributeKey[List[Option[String]]]("on-failure-stack", "Stack that remembers on-failure handlers.", 10)
diff --git a/main/command/src/main/scala/sbt/internal/NetworkChannel.scala b/main/command/src/main/scala/sbt/internal/NetworkChannel.scala
index 3d44a7b6a..701a4ecdb 100644
--- a/main/command/src/main/scala/sbt/internal/NetworkChannel.scala
+++ b/main/command/src/main/scala/sbt/internal/NetworkChannel.scala
@@ -2,12 +2,18 @@ package sbt
 package internal
 
 import sbt.internal.server._
+import BasicKeys._
 
 private[sbt] final class NetworkChannel(exchange: CommandExchange) extends CommandChannel(exchange) {
   private var server: Option[ServerInstance] = None
 
   def runOrResume(status: CommandStatus): Unit =
     {
+      val s = status.state
+      val port = (s get serverPort) match {
+        case Some(x) => x
+        case None    => 5001
+      }
       def onCommand(command: internal.server.Command): Unit = {
         command match {
           case Execution(cmd) => exchange.append(CommandRequest(CommandSource.Network, cmd))
@@ -16,7 +22,7 @@ private[sbt] final class NetworkChannel(exchange: CommandExchange) extends Comma
       server match {
         case Some(x) => // do nothing
         case _ =>
-          server = Some(Server.start("127.0.0.1", 12700, onCommand))
+          server = Some(Server.start("127.0.0.1", port, onCommand))
       }
     }
 
diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index ed54a98be..049bdbcfa 100755
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -41,7 +41,7 @@ import sbt.util.InterfaceUtil.{ f1, o2m }
 import sbt.internal.util.Types._
 
 import sbt.internal.io.WatchState
-import sbt.io.{ AllPassFilter, FileFilter, GlobFilter, HiddenFileFilter, IO, NameFilter, NothingFilter, Path, PathFinder, SimpleFileFilter, DirectoryFilter }
+import sbt.io.{ AllPassFilter, FileFilter, GlobFilter, HiddenFileFilter, IO, NameFilter, NothingFilter, Path, PathFinder, SimpleFileFilter, DirectoryFilter, Hash }
 
 import Path._
 import sbt.io.syntax._
@@ -200,7 +200,8 @@ object Defaults extends BuildCommon {
     fork :== false,
     initialize :== {},
     forcegc :== sys.props.get("sbt.task.forcegc").map(java.lang.Boolean.parseBoolean).getOrElse(GCUtil.defaultForceGarbageCollection),
-    minForcegcInterval :== GCUtil.defaultMinForcegcInterval
+    minForcegcInterval :== GCUtil.defaultMinForcegcInterval,
+    serverPort := 5000 + (Hash.toHex(Hash(appConfiguration.value.baseDirectory.toString)).## % 1000)
   ))
   def defaultTestTasks(key: Scoped): Seq[Setting[_]] = inTask(key)(Seq(
     tags := Seq(Tags.Test -> 1),
diff --git a/main/src/main/scala/sbt/Keys.scala b/main/src/main/scala/sbt/Keys.scala
index ee21d78b8..33ac5f3f2 100644
--- a/main/src/main/scala/sbt/Keys.scala
+++ b/main/src/main/scala/sbt/Keys.scala
@@ -114,6 +114,7 @@ object Keys {
   // Command keys
   val historyPath = SettingKey(BasicKeys.historyPath)
   val shellPrompt = SettingKey(BasicKeys.shellPrompt)
+  val serverPort = SettingKey(BasicKeys.serverPort)
   val analysis = AttributeKey[CompileAnalysis]("analysis", "Analysis of compilation, including dependencies and generated outputs.", DSetting)
   val watch = SettingKey(BasicKeys.watch)
   val pollInterval = SettingKey[Int]("poll-interval", "Interval between checks for modified sources by the continuous execution command.", BMinusSetting)
diff --git a/main/src/main/scala/sbt/Project.scala b/main/src/main/scala/sbt/Project.scala
index dce3233e5..7ddcc6c82 100755
--- a/main/src/main/scala/sbt/Project.scala
+++ b/main/src/main/scala/sbt/Project.scala
@@ -6,9 +6,8 @@ package sbt
 import java.io.File
 import java.net.URI
 import java.util.Locale
-import Project._
-import Keys.{ stateBuildStructure, commands, configuration, historyPath, projectCommand, sessionSettings,
-  shellPrompt, watch }
+import Project.{ Initialize => _, Setting => _, _ }
+import Keys.{ appConfiguration, stateBuildStructure, commands, configuration, historyPath, projectCommand, sessionSettings, shellPrompt, serverPort, thisProject, thisProjectRef, watch }
 import Scope.{ GlobalScope, ThisScope }
 import Def.{ Flattened, Initialize, ScopedKey, Setting }
 import sbt.internal.{ Load, BuildStructure, LoadedBuild, LoadedBuildUnit, SettingGraph, SettingCompletions, AddSettings, SessionSettings }
@@ -417,9 +416,11 @@ object Project extends ProjectExtra {
       val history = get(historyPath) flatMap idFun
       val prompt = get(shellPrompt)
       val watched = get(watch)
+      val port: Option[Int] = get(serverPort)
       val commandDefs = allCommands.distinct.flatten[Command].map(_ tag (projectCommand, true))
       val newDefinedCommands = commandDefs ++ BasicCommands.removeTagged(s.definedCommands, projectCommand)
-      val newAttrs = setCond(Watched.Configuration, watched, s.attributes).put(historyPath.key, history)
+      val newAttrs0 = setCond(Watched.Configuration, watched, s.attributes).put(historyPath.key, history)
+      val newAttrs = setCond(serverPort.key, port, newAttrs0)
       s.copy(attributes = setCond(shellPrompt.key, prompt, newAttrs), definedCommands = newDefinedCommands)
     }
   def setCond[T](key: AttributeKey[T], vopt: Option[T], attributes: AttributeMap): AttributeMap =