diff --git a/configure.py b/configure.py
index f0b9fad..9fd2dc2 100644
--- a/configure.py
+++ b/configure.py
@@ -54,6 +54,12 @@
 _TF_BAZELRC = os.path.join(_TF_WORKSPACE_ROOT, _TF_BAZELRC_FILENAME)
 _TF_WORKSPACE = os.path.join(_TF_WORKSPACE_ROOT, 'WORKSPACE')
 
+NCCL_LIB_PATHS = [
+  "lib64/",
+  "lib/powerpc64le-linux-gnu/",
+  "lib/x86_64-linux-gnu/",
+  ""
+]
 
 class UserInputError(Exception):
   pass
@@ -1085,7 +1091,7 @@
 
 
 def set_tf_nccl_install_path(environ_cp):
-  """Set NCCL_INSTALL_PATH and TF_NCCL_VERSION.
+  """Set NCCL_INSTALL_PATH, NCCL_HDR_PATH and TF_NCCL_VERSION.
 
   Args:
     environ_cp: copy of the os.environ.
@@ -1111,46 +1117,98 @@
     if tf_nccl_version == '1':
       break  # No need to get install path, NCCL 1 is a GitHub repo.
 
-    # TODO(csigg): Look with ldconfig first if we can find the library in paths
+    # Look with ldconfig first if we can find the library in paths
     # like /usr/lib/x86_64-linux-gnu and the header file in the corresponding
     # include directory. This is where the NCCL .deb packages install them.
-    # Then ask the user if we should use that. Instead of a single
-    # NCCL_INSTALL_PATH, pass separate NCCL_LIB_PATH and NCCL_HDR_PATH to
-    # nccl_configure.bzl
-    default_nccl_path = environ_cp.get('CUDA_TOOLKIT_PATH')
-    ask_nccl_path = (r'Please specify the location where NCCL %s library is '
+
+    # First check to see if NCCL is in the ldconfig.
+    # If its found, use that location.
+    if is_linux():
+      ldconfig_bin = which('ldconfig') or '/sbin/ldconfig'
+      nccl2_path_from_ldconfig = run_shell([ldconfig_bin, '-p'])
+      nccl2_path_from_ldconfig = re.search('.*libnccl.so .* => (.*)',
+                                           nccl2_path_from_ldconfig)
+    if nccl2_path_from_ldconfig:
+      nccl2_path_from_ldconfig = nccl2_path_from_ldconfig.group(1)
+      if os.path.exists('%s.%s' % (nccl2_path_from_ldconfig, tf_nccl_version)):
+        nccl_install_path = os.path.dirname(nccl2_path_from_ldconfig)
+        print('NCCL libraries found in ' + nccl2_path_from_ldconfig)
+        
+        # Check if this is the main system lib location
+        if re.search('.*linux-gnu', nccl_install_path):
+          trunc_nccl_install_path = "/usr"
+          print("This looks like a system path.")
+        else:
+          trunc_nccl_install_path = nccl_install_path + "/.."
+  
+        # Look for header
+        nccl_hdr_path = trunc_nccl_install_path + "/include"
+        print("Assuming NCCL header path is " + nccl_hdr_path)
+        if os.path.exists(nccl_hdr_path + "/nccl.h"):
+          # Set NCCL_INSTALL_PATH
+          environ_cp['NCCL_INSTALL_PATH'] = nccl_install_path
+          write_action_env_to_bazelrc('NCCL_INSTALL_PATH', nccl_install_path)
+
+          # Set NCCL_HDR_PATH
+          environ_cp['NCCL_HDR_PATH'] = nccl_hdr_path
+          write_action_env_to_bazelrc('NCCL_HDR_PATH', nccl_hdr_path)
+          break
+        else:
+          print('The header for NCCL2 cannot be found. Please install the libnccl-dev package.')
+      else:
+          print('NCCL2 is listed by ldconfig but the library is not found. ' 
+                'Your ldconfig is out of date. Please run sudo ldconfig.')
+    else:
+      # NCCL is not found in ldconfig. Ask the user for the location.
+      default_nccl_path = environ_cp.get('CUDA_TOOLKIT_PATH')
+      ask_nccl_path = (r'Please specify the location where NCCL %s library is '
                      'installed. Refer to README.md for more details. [Default '
                      'is %s]:') % (tf_nccl_version, default_nccl_path)
-    nccl_install_path = get_from_env_or_user_or_default(
+      nccl_install_path = get_from_env_or_user_or_default(
         environ_cp, 'NCCL_INSTALL_PATH', ask_nccl_path, default_nccl_path)
 
-    # Result returned from "read" will be used unexpanded. That make "~"
-    # unusable. Going through one more level of expansion to handle that.
-    nccl_install_path = os.path.realpath(os.path.expanduser(nccl_install_path))
-    if is_windows() or is_cygwin():
-      nccl_install_path = cygpath(nccl_install_path)
+      # Result returned from "read" will be used unexpanded. That make "~"
+      # unusable. Going through one more level of expansion to handle that.
+      nccl_install_path = os.path.realpath(os.path.expanduser(nccl_install_path))
+      if is_windows() or is_cygwin():
+        nccl_install_path = cygpath(nccl_install_path)
 
-    if is_windows():
-      nccl_lib_path = 'lib/x64/nccl.lib'
-    elif is_linux():
-      nccl_lib_path = 'lib/libnccl.so.%s' % tf_nccl_version
-    elif is_macos():
-      nccl_lib_path = 'lib/libnccl.%s.dylib' % tf_nccl_version
+      if is_windows():
+        nccl_lib_path = 'lib/x64/nccl.lib'
+      elif is_linux():
+        nccl_lib_filename = 'libnccl.so.%s' % tf_nccl_version
+        nccl_lpath = '%s/lib/%s' % (nccl_install_path, nccl_lib_filename)
+        if not os.path.exists(nccl_lpath):
+          for relative_path in NCCL_LIB_PATHS:
+            path = '%s/%s%s' % (nccl_install_path, relative_path, nccl_lib_filename)
+            if os.path.exists(path):
+              print("NCCL found at " + path)
+              nccl_lib_path = path
+              break
+        else:
+          nccl_lib_path = nccl_lpath
+      elif is_macos():
+        nccl_lib_path = 'lib/libnccl.%s.dylib' % tf_nccl_version
 
-    nccl_lib_path = os.path.join(nccl_install_path, nccl_lib_path)
-    nccl_hdr_path = os.path.join(nccl_install_path, 'include/nccl.h')
-    if os.path.exists(nccl_lib_path) and os.path.exists(nccl_hdr_path):
-      # Set NCCL_INSTALL_PATH
-      environ_cp['NCCL_INSTALL_PATH'] = nccl_install_path
-      write_action_env_to_bazelrc('NCCL_INSTALL_PATH', nccl_install_path)
-      break
+      nccl_lib_path = os.path.join(nccl_install_path, nccl_lib_path)
+      nccl_hdr_path = os.path.join(os.path.dirname(nccl_lib_path), '../include/nccl.h')
+      print("Assuming NCCL header path is "+nccl_hdr_path)
+      if os.path.exists(nccl_lib_path) and os.path.exists(nccl_hdr_path):
+        # Set NCCL_INSTALL_PATH
+        environ_cp['NCCL_INSTALL_PATH'] = os.path.dirname(nccl_lib_path)
+        write_action_env_to_bazelrc('NCCL_INSTALL_PATH', os.path.dirname(nccl_lib_path))
 
-    # Reset and Retry
-    print('Invalid path to NCCL %s toolkit, %s or %s not found. Please use the '
-          'O/S agnostic package of NCCL 2' % (tf_nccl_version, nccl_lib_path,
+        # Set NCCL_HDR_PATH
+        environ_cp['NCCL_HDR_PATH'] = os.path.dirname(nccl_hdr_path)
+        write_action_env_to_bazelrc('NCCL_HDR_PATH', os.path.dirname(nccl_hdr_path))
+        break
+
+      # Reset and Retry
+      print('Invalid path to NCCL %s toolkit, %s or %s not found. Please use the '
+            'O/S agnostic package of NCCL 2' % (tf_nccl_version, nccl_lib_path,
                                               nccl_hdr_path))
 
-    environ_cp['TF_NCCL_VERSION'] = ''
+      environ_cp['TF_NCCL_VERSION'] = ''
   else:
     raise UserInputError('Invalid TF_NCCL setting was provided %d '
                          'times in a row. Assuming to be a scripting mistake.' %
@@ -1401,20 +1459,10 @@
 
 def set_system_libs_flag(environ_cp):
   syslibs = environ_cp.get('TF_SYSTEM_LIBS', '')
+  syslibs = ','.join(sorted(syslibs.split(',')))
   if syslibs and syslibs != '':
-    if ',' in syslibs:
-      syslibs = ','.join(sorted(syslibs.split(',')))
-    else:
-      syslibs = ','.join(sorted(syslibs.split()))
     write_action_env_to_bazelrc('TF_SYSTEM_LIBS', syslibs)
 
-  if 'PREFIX' in environ_cp:
-    write_to_bazelrc('build --define=PREFIX=%s' % environ_cp['PREFIX'])
-  if 'LIBDIR' in environ_cp:
-    write_to_bazelrc('build --define=LIBDIR=%s' % environ_cp['LIBDIR'])
-  if 'INCLUDEDIR' in environ_cp:
-    write_to_bazelrc('build --define=INCLUDEDIR=%s' % environ_cp['INCLUDEDIR'])
-
 
 def set_windows_build_flags(environ_cp):
   """Set Windows specific build options."""