diff --git a/pcsx2/DEV9/Sessions/TCP_Session/TCP_Session_In.cpp b/pcsx2/DEV9/Sessions/TCP_Session/TCP_Session_In.cpp
index f003613a20..138ab13c0e 100644
--- a/pcsx2/DEV9/Sessions/TCP_Session/TCP_Session_In.cpp
+++ b/pcsx2/DEV9/Sessions/TCP_Session/TCP_Session_In.cpp
@@ -80,7 +80,7 @@ namespace Sessions
 			int err = 0;
 			int recived;
 
-			u_long available;
+			unsigned long available;
 #ifdef _WIN32
 			err = ioctlsocket(client, FIONREAD, &available);
 #elif defined(__POSIX__)
diff --git a/pcsx2/DEV9/Sessions/UDP_Session/UDP_FixedPort.cpp b/pcsx2/DEV9/Sessions/UDP_Session/UDP_FixedPort.cpp
index 6c1f5b377f..fcc1e429c4 100644
--- a/pcsx2/DEV9/Sessions/UDP_Session/UDP_FixedPort.cpp
+++ b/pcsx2/DEV9/Sessions/UDP_Session/UDP_FixedPort.cpp
@@ -8,6 +8,7 @@
 #define SOCKET_ERROR -1
 #include <errno.h>
 #include <sys/ioctl.h>
+#include <sys/select.h>
 #include <netinet/in.h>
 #endif
 
@@ -132,7 +133,7 @@ namespace Sessions
 
 		if (hasData)
 		{
-			u_long available = 0;
+			unsigned long available = 0;
 			PayloadData* recived = nullptr;
 			std::unique_ptr<u8[]> buffer;
 			sockaddr endpoint{0};
diff --git a/pcsx2/DEV9/Sessions/UDP_Session/UDP_Session.cpp b/pcsx2/DEV9/Sessions/UDP_Session/UDP_Session.cpp
index 372d4882aa..fe71041097 100644
--- a/pcsx2/DEV9/Sessions/UDP_Session/UDP_Session.cpp
+++ b/pcsx2/DEV9/Sessions/UDP_Session/UDP_Session.cpp
@@ -8,6 +8,7 @@
 #define SOCKET_ERROR -1
 #include <errno.h>
 #include <sys/ioctl.h>
+#include <sys/select.h>
 #include <netinet/in.h>
 #endif
 
@@ -119,7 +120,7 @@ namespace Sessions
 
 		if (hasData)
 		{
-			u_long available = 0;
+			unsigned long available = 0;
 			PayloadData* recived = nullptr;
 			std::unique_ptr<u8[]> buffer;
 			sockaddr endpoint{0};