diff --git a/ivy/Ivy.scala b/ivy/Ivy.scala
index b59f639a8..002618fad 100644
--- a/ivy/Ivy.scala
+++ b/ivy/Ivy.scala
@@ -65,7 +65,7 @@ final class IvySbt(val configuration: IvyConfiguration)
 		CustomPomParser.registerDefault
 		configuration match
 		{
-			case e: ExternalIvyConfiguration => is.load(e.file)
+			case e: ExternalIvyConfiguration => is.load(e.url)
 			case i: InlineIvyConfiguration =>
 				is.setVariable("ivy.checksums", i.checksums mkString ",")
 				i.paths.ivyHome foreach is.setDefaultIvyUserDir
diff --git a/ivy/IvyConfigurations.scala b/ivy/IvyConfigurations.scala
index 317d20c67..c3999ea6f 100644
--- a/ivy/IvyConfigurations.scala
+++ b/ivy/IvyConfigurations.scala
@@ -4,6 +4,7 @@
 package sbt
 
 import java.io.File
+import java.net.URL
 import scala.xml.NodeSeq
 
 final class IvyPaths(val baseDirectory: File, val ivyHome: Option[File])
@@ -27,10 +28,14 @@ final class InlineIvyConfiguration(val paths: IvyPaths, val resolvers: Seq[Resol
 	def withBase(newBase: File) = new InlineIvyConfiguration(paths.withBase(newBase), resolvers, otherResolvers, moduleConfigurations, localOnly, lock, checksums, log)
 	def changeResolvers(newResolvers: Seq[Resolver]) = new InlineIvyConfiguration(paths, newResolvers, otherResolvers, moduleConfigurations, localOnly, lock, checksums, log)
 }
-final class ExternalIvyConfiguration(val baseDirectory: File, val file: File, val lock: Option[xsbti.GlobalLock], val log: Logger) extends IvyConfiguration
+final class ExternalIvyConfiguration(val baseDirectory: File, val url: URL, val lock: Option[xsbti.GlobalLock], val log: Logger) extends IvyConfiguration
 {
 	type This = ExternalIvyConfiguration
-	def withBase(newBase: File) = new ExternalIvyConfiguration(newBase, file, lock, log)
+	def withBase(newBase: File) = new ExternalIvyConfiguration(newBase, url, lock, log)
+}
+object ExternalIvyConfiguration
+{
+	def apply(baseDirectory: File, file: File, lock: Option[xsbti.GlobalLock], log: Logger) = new ExternalIvyConfiguration(baseDirectory, file.toURI.toURL, lock, log)
 }
 
 object IvyConfiguration
@@ -42,7 +47,7 @@ object IvyConfiguration
 		log.debug("Autodetecting configuration.")
 		val defaultIvyConfigFile = IvySbt.defaultIvyConfiguration(paths.baseDirectory)
 		if(defaultIvyConfigFile.canRead)
-			new ExternalIvyConfiguration(paths.baseDirectory, defaultIvyConfigFile, lock, log)
+			ExternalIvyConfiguration(paths.baseDirectory, defaultIvyConfigFile, lock, log)
 		else
 			new InlineIvyConfiguration(paths, Resolver.withDefaultResolvers(Nil), Nil, Nil, localOnly, lock, checksums, log)
 	}
diff --git a/main/Defaults.scala b/main/Defaults.scala
index 528bcfc48..0a4e86f89 100755
--- a/main/Defaults.scala
+++ b/main/Defaults.scala
@@ -1252,10 +1252,13 @@ trait BuildExtra extends BuildCommon
 	def seq(settings: Setting[_]*): SettingsDefinition = new Project.SettingList(settings)
 
 	def externalIvySettings(file: Initialize[File] = baseDirectory / "ivysettings.xml"): Setting[Task[IvyConfiguration]] =
+		externalIvySettingsUrl(file(_.toURI.toURL))
+	def externalIvySettings(url: URL): Setting[Task[IvyConfiguration]] = externalIvySettingsUrl(new Project.Value(() => url))
+	private def externalIvySettingsUrl(url: Initialize[URL]): Setting[Task[IvyConfiguration]] =
 	{
 		val other = (baseDirectory, appConfiguration, streams).identityMap
-		ivyConfiguration <<= (file zipWith other) { case (f, otherTask) =>
-			otherTask map { case (base, app, s) => new ExternalIvyConfiguration(base, f, Some(lock(app)), s.log) }
+		ivyConfiguration <<= (url zipWith other) { case (u, otherTask) =>
+			otherTask map { case (base, app, s) => new ExternalIvyConfiguration(base, u, Some(lock(app)), s.log) }
 		}
 	}
 	def externalIvyFile(file: Initialize[File] = baseDirectory / "ivy.xml", iScala: Initialize[Option[IvyScala]] = ivyScala): Setting[Task[ModuleSettings]] =
diff --git a/main/actions/CacheIvy.scala b/main/actions/CacheIvy.scala
index dffd76c49..e685b7eb8 100644
--- a/main/actions/CacheIvy.scala
+++ b/main/actions/CacheIvy.scala
@@ -186,7 +186,11 @@ object CacheIvy
 		implicit def fileConfToHL = (f: FileConfiguration) => f.isLocal :+: f.isTransactional :+: HNil
 
 		implicit def externalIvyConfigurationToHL = (e: ExternalIvyConfiguration) =>
-			exists(e.baseDirectory) :+: hash(e.file) :+: HNil
+			exists(e.baseDirectory) :+:
+				(e.url match {
+					case u: URL if u.getProtocol == "file" => Hash(u)
+					case u: URL => Hash(u.toURI.normalize.toString)
+				}) :+: HNil
 	}
 	import L1._
 
diff --git a/util/io/Hash.scala b/util/io/Hash.scala
index 6b44cea5e..71d661530 100644
--- a/util/io/Hash.scala
+++ b/util/io/Hash.scala
@@ -4,6 +4,7 @@
 package sbt
 
 import java.io.{ByteArrayInputStream, File, InputStream}
+import java.net.URL
 
 object Hash
 {
@@ -42,6 +43,8 @@ object Hash
 	def apply(as: Array[Byte]): Array[Byte] = apply(new ByteArrayInputStream(as))
 	/** Calculates the SHA-1 hash of the given file.*/
 	def apply(file: File): Array[Byte] = Using.fileInputStream(file)(apply)
+	/** Calculates the SHA-1 hash of the given resource.*/
+	def apply(url: URL): Array[Byte] = Using.urlInputStream(url)(apply)
 	/** Calculates the SHA-1 hash of the given stream, closing it when finished.*/
 	def apply(stream: InputStream): Array[Byte] =
 	{