diff --git a/aos/common/Configuration.h b/aos/common/Configuration.h
new file mode 100644
index 0000000..bf2dc80
--- /dev/null
+++ b/aos/common/Configuration.h
@@ -0,0 +1,42 @@
+#ifndef AOS_COMMON_CONFIGURATION_H_
+#define AOS_COMMON_CONFIGURATION_H_
+
+#include "aos/aos_stdint.h"
+
+namespace aos {
+
+// Constants representing the various ports used for communications and some
+// documentation about what each is used for.
+enum class NetworkPort : uint16_t {
+  // UDP socket sending motor values from the atom to the crio.
+  kMotors = 9710,
+  // UDP socket forwarding drivers station packets from the crio to the atom.
+  kDS = 9711,
+  // UDP socket sending sensor values from the crio to the atom.
+  kSensors = 9712,
+  // TCP socket(s) (automatically reconnects) sending logs from the crio to the
+  // atom.
+  kLogs = 9713,
+  // HTTP server that sends out camera feeds in mjpg format.
+  // Should not be changed because this number shows up elsewhere too.
+  kCameraStreamer = 9714,
+};
+
+// Holds global configuration data. All of the public static functions are safe
+// to call concurrently (the ones that need to create locks on the cRIO).
+namespace configuration {
+
+// Constants indentifying various devices on the network.
+enum class NetworkDevice {
+  // The computer that the cRIO talks to.
+  kAtom,
+  kCRIO,
+};
+// Returns the IP address to get to the specified machine.
+// The return value should be passed to free(3) if it is no longer needed.
+const char *GetIPAddress(NetworkDevice device);
+
+}  // namespace configuration
+}  // namespace aos
+
+#endif