diff --git a/MasterPassword/C/mpw-algorithm_v0.c b/MasterPassword/C/mpw-algorithm_v0.c
index 3873a9ff..a28868d0 100644
--- a/MasterPassword/C/mpw-algorithm_v0.c
+++ b/MasterPassword/C/mpw-algorithm_v0.c
@@ -8,6 +8,7 @@
 
 #include <string.h>
 #include <errno.h>
+#include <arpa/inet.h>
 
 #include "mpw-types.h"
 #include "mpw-util.h"
diff --git a/MasterPassword/C/mpw-algorithm_v1.c b/MasterPassword/C/mpw-algorithm_v1.c
index 300002f5..77e0662d 100644
--- a/MasterPassword/C/mpw-algorithm_v1.c
+++ b/MasterPassword/C/mpw-algorithm_v1.c
@@ -8,6 +8,7 @@
 
 #include <string.h>
 #include <errno.h>
+#include <arpa/inet.h>
 
 #include "mpw-types.h"
 #include "mpw-util.h"
diff --git a/MasterPassword/C/mpw-algorithm_v2.c b/MasterPassword/C/mpw-algorithm_v2.c
index 25153b72..227fc2e2 100644
--- a/MasterPassword/C/mpw-algorithm_v2.c
+++ b/MasterPassword/C/mpw-algorithm_v2.c
@@ -8,6 +8,7 @@
 
 #include <string.h>
 #include <errno.h>
+#include <arpa/inet.h>
 
 #include "mpw-types.h"
 #include "mpw-util.h"
diff --git a/MasterPassword/C/mpw-algorithm_v3.c b/MasterPassword/C/mpw-algorithm_v3.c
index 30a21516..64154d4e 100644
--- a/MasterPassword/C/mpw-algorithm_v3.c
+++ b/MasterPassword/C/mpw-algorithm_v3.c
@@ -8,6 +8,7 @@
 
 #include <string.h>
 #include <errno.h>
+#include <arpa/inet.h>
 
 #include "mpw-types.h"
 #include "mpw-util.h"