diff --git a/core/src/main/kotlin/net/corda/core/internal/InternalUtils.kt b/core/src/main/kotlin/net/corda/core/internal/InternalUtils.kt
index a7aa8624c4..3632d5a9c0 100644
--- a/core/src/main/kotlin/net/corda/core/internal/InternalUtils.kt
+++ b/core/src/main/kotlin/net/corda/core/internal/InternalUtils.kt
@@ -33,6 +33,7 @@ import java.io.*
 import java.lang.reflect.Field
 import java.math.BigDecimal
 import java.net.HttpURLConnection
+import java.net.HttpURLConnection.HTTP_OK
 import java.net.URL
 import java.nio.ByteBuffer
 import java.nio.charset.Charset
@@ -352,10 +353,11 @@ val KClass<*>.packageName: String get() = java.`package`.name
 
 fun URL.openHttpConnection(): HttpURLConnection = openConnection() as HttpURLConnection
 
-fun URL.post(serializedData: OpaqueBytes): ByteArray {
+fun URL.post(serializedData: OpaqueBytes, vararg properties: Pair<String, String>): ByteArray {
     return openHttpConnection().run {
         doOutput = true
         requestMethod = "POST"
+        properties.forEach { (key, value) -> setRequestProperty(key, value) }
         setRequestProperty("Content-Type", "application/octet-stream")
         outputStream.use { serializedData.open().copyTo(it) }
         checkOkResponse()
@@ -364,12 +366,13 @@ fun URL.post(serializedData: OpaqueBytes): ByteArray {
 }
 
 fun HttpURLConnection.checkOkResponse() {
-    if (responseCode != 200) {
-        val message = errorStream.use { it.reader().readText() }
-        throw IOException("Response Code $responseCode: $message")
+    if (responseCode != HTTP_OK) {
+        throw IOException("Response Code $responseCode: $errorMessage")
     }
 }
 
+val HttpURLConnection.errorMessage: String? get() = errorStream?.let { it.use { it.reader().readText() } }
+
 inline fun <reified T : Any> HttpURLConnection.responseAs(): T {
     checkOkResponse()
     return inputStream.readObject()
diff --git a/node/src/main/kotlin/net/corda/node/services/network/NetworkMapClient.kt b/node/src/main/kotlin/net/corda/node/services/network/NetworkMapClient.kt
index 4508b7753b..7bd6b7aec9 100644
--- a/node/src/main/kotlin/net/corda/node/services/network/NetworkMapClient.kt
+++ b/node/src/main/kotlin/net/corda/node/services/network/NetworkMapClient.kt
@@ -48,7 +48,7 @@ class NetworkMapClient(compatibilityZoneURL: URL, val trustedRoot: X509Certifica
         val connection = networkMapUrl.openHttpConnection()
         val signedNetworkMap = connection.responseAs<SignedNetworkMap>()
         val networkMap = signedNetworkMap.verifiedNetworkMapCert(trustedRoot)
-        val timeout = connection.cacheControl().maxAgeSeconds().seconds
+        val timeout = connection.cacheControl.maxAgeSeconds().seconds
         logger.trace { "Fetched network map update from $networkMapUrl successfully: $networkMap" }
         return NetworkMapResponse(networkMap, timeout)
     }
diff --git a/node/src/main/kotlin/net/corda/node/utilities/registration/HTTPNetworkRegistrationService.kt b/node/src/main/kotlin/net/corda/node/utilities/registration/HTTPNetworkRegistrationService.kt
index 7f3d0ddf24..6cf4b0e369 100644
--- a/node/src/main/kotlin/net/corda/node/utilities/registration/HTTPNetworkRegistrationService.kt
+++ b/node/src/main/kotlin/net/corda/node/utilities/registration/HTTPNetworkRegistrationService.kt
@@ -1,12 +1,13 @@
 package net.corda.node.utilities.registration
 
-import com.google.common.net.MediaType
+import net.corda.core.internal.errorMessage
 import net.corda.core.internal.openHttpConnection
+import net.corda.core.internal.post
+import net.corda.core.utilities.OpaqueBytes
 import net.corda.core.utilities.seconds
 import net.corda.nodeapi.internal.crypto.X509CertificateFactory
 import okhttp3.CacheControl
 import okhttp3.Headers
-import org.apache.commons.io.IOUtils
 import org.bouncycastle.pkcs.PKCS10CertificationRequest
 import java.io.IOException
 import java.net.HttpURLConnection
@@ -21,7 +22,7 @@ class HTTPNetworkRegistrationService(compatibilityZoneURL: URL) : NetworkRegistr
 
     companion object {
         // TODO: Propagate version information from gradle
-        val clientVersion = "1.0"
+        const val CLIENT_VERSION = "1.0"
     }
 
     @Throws(CertificateRequestException::class)
@@ -29,7 +30,7 @@ class HTTPNetworkRegistrationService(compatibilityZoneURL: URL) : NetworkRegistr
         // Poll server to download the signed certificate once request has been approved.
         val conn = URL("$registrationURL/$requestId").openHttpConnection()
         conn.requestMethod = "GET"
-        val maxAge = conn.cacheControl().maxAgeSeconds()
+        val maxAge = conn.cacheControl.maxAgeSeconds()
         // Default poll interval to 10 seconds if not specified by the server, for backward compatibility.
         val pollInterval = if (maxAge == -1) 10.seconds else maxAge.seconds
 
@@ -44,33 +45,15 @@ class HTTPNetworkRegistrationService(compatibilityZoneURL: URL) : NetworkRegistr
             }
             HTTP_NO_CONTENT -> CertificateResponse(pollInterval, null)
             HTTP_UNAUTHORIZED -> throw CertificateRequestException("Certificate signing request has been rejected: ${conn.errorMessage}")
-            else -> throwUnexpectedResponseCode(conn)
+            else -> throw IOException("Response Code ${conn.responseCode}: ${conn.errorMessage}")
         }
     }
 
     override fun submitRequest(request: PKCS10CertificationRequest): String {
-        // Post request to certificate signing server via http.
-        val conn = URL("$registrationURL").openHttpConnection()
-        conn.doOutput = true
-        conn.requestMethod = "POST"
-        conn.setRequestProperty("Content-Type", "application/octet-stream")
-        conn.setRequestProperty("Client-Version", clientVersion)
-        conn.outputStream.write(request.encoded)
-
-        return when (conn.responseCode) {
-            HTTP_OK -> IOUtils.toString(conn.inputStream, conn.charset)
-            HTTP_FORBIDDEN -> throw IOException("Client version $clientVersion is forbidden from accessing permissioning server, please upgrade to newer version.")
-            else -> throwUnexpectedResponseCode(conn)
-        }
+        return String(registrationURL.post(OpaqueBytes(request.encoded), "Client-Version" to CLIENT_VERSION))
     }
-
-    private fun throwUnexpectedResponseCode(connection: HttpURLConnection): Nothing {
-        throw IOException("Unexpected response code ${connection.responseCode} - ${connection.errorMessage}")
-    }
-
-    private val HttpURLConnection.charset: String get() = MediaType.parse(contentType).charset().or(Charsets.UTF_8).name()
-
-    private val HttpURLConnection.errorMessage: String get() = IOUtils.toString(errorStream, charset)
 }
 
-fun HttpURLConnection.cacheControl(): CacheControl = CacheControl.parse(Headers.of(headerFields.filterKeys { it != null }.mapValues { it.value[0] }))
+val HttpURLConnection.cacheControl: CacheControl get() {
+    return CacheControl.parse(Headers.of(headerFields.filterKeys { it != null }.mapValues { it.value[0] }))
+}