diff --git a/src/configuration.cpp b/src/configuration.cpp
index b400a2f..5b01efc 100644
--- a/src/configuration.cpp
+++ b/src/configuration.cpp
@@ -185,6 +185,8 @@
 
 } // namespace ca
 
+namespace requester {
+
 void
 RequesterCaCache::load(const std::string& fileName)
 {
@@ -249,5 +251,6 @@
   m_caItems.push_back(profile);
 }
 
+} // namespace requester
 } // namespace ndncert
 } // namespace ndn