diff --git a/src/cip.cpp b/src/cip.cpp
index 7717e05..dfd5ec1 100644
--- a/src/cip.cpp
+++ b/src/cip.cpp
@@ -31,10 +31,10 @@
 ////////////////////////////////////////////////////////////////////////////////////////
 // constructors
 
-CIp::CIp()
+CIp::CIp(const int af)
 {
     ::memset(&m_Addr, 0, m_AddrLen = sizeof(struct sockaddr_in));
-    m_Addr.ss_family = AF_INET;
+    m_Addr.ss_family = af;
 }
 
 CIp::CIp(const char *sz)
diff --git a/src/cip.h b/src/cip.h
index 2827fea..8356378 100644
--- a/src/cip.h
+++ b/src/cip.h
@@ -33,7 +33,7 @@ class CIp
 {
 public:
     // constructors
-    CIp();
+    CIp(const int af = AF_INET);
     //CIp(uint8, uint8, uint8, uint8);
     CIp(const struct sockaddr_storage *, socklen_t);
     CIp(const char *);