diff --git a/configure.ac b/configure.ac
index 7ad323be2..a5d6088bd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -177,9 +177,21 @@ fi
 AC_CHECK_HEADER(srtp2/srtp.h, found_libsrtp2=yes)
 if test "$found_libsrtp2" = yes
 then
-  AC_CHECK_LIB(srtp2, srtp_init,
+  AC_CHECK_LIB(srtp2, srtp_init,[
    LIBS_SRTP="-lsrtp2"
-   AC_DEFINE([ENABLE_SRTP2], 1, [Define if you have libsrtp2 library installed]))
+   # Test program to check if the srtp_protect function accepts size_t* argument
+   AC_MSG_CHECKING(['srtp_protect()' last argument type])
+   original_cflags="$CFLAGS"
+   CFLAGS="$CFLAGS -Werror"
+   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
+     #include <stdlib.h>
+     #include <srtp2/srtp.h>],
+     [srtp_t ctx; void* rtp_hdr; size_t len; return srtp_protect(ctx, rtp_hdr, &len);])],
+     [srtp_protect_lastarg=size_t], [srtp_protect_lastarg=int])
+   CFLAGS="$original_cflags"
+   AC_MSG_RESULT([$srtp_protect_lastarg])
+   AC_DEFINE_UNQUOTED([SRTP_PROTECT_LASTARG], [${srtp_protect_lastarg}], [Type of the last argument of the srtp_protect() API])
+   AC_DEFINE([ENABLE_SRTP2], 1, [Define if you have libsrtp2 library installed])])
 else
   # libsrtp
   AC_CHECK_HEADER(srtp/srtp.h, found_libsrtp=yes)
diff --git a/modules/dtls_gw/rtpp_dtls_conn.c b/modules/dtls_gw/rtpp_dtls_conn.c
index e5519ba5c..423881273 100644
--- a/modules/dtls_gw/rtpp_dtls_conn.c
+++ b/modules/dtls_gw/rtpp_dtls_conn.c
@@ -454,7 +454,12 @@ rtpp_dtls_conn_dtls_recv(struct rtpp_dtls_conn *self,
 static int
 rtpp_dtls_conn_rtp_send(struct rtpp_dtls_conn *self, struct pkt_proc_ctx *pktxp)
 {
-    int status, len;
+    int status;
+#if defined(SRTP_PROTECT_LASTARG)
+    SRTP_PROTECT_LASTARG len;
+#else
+    size_t len;
+#endif
     struct rtpp_dtls_conn_priv *pvt;
 
     PUB2PVT(self, pvt);
diff --git a/src/config.h.in b/src/config.h.in
index ea7f70a0b..3d1cfff7e 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -211,6 +211,9 @@
 /* The number of bytes in type time_t */
 #undef SIZEOF_TIME_T
 
+/* Type of the last argument of the srtp_protect() API */
+#undef SRTP_PROTECT_LASTARG
+
 /* If using the C implementation of alloca, define if you know the
    direction of stack growth for your system; otherwise it will be
    automatically deduced at runtime.