diff --git a/src/network/core/core.c b/src/network/core/core.c
index a4131bdf2a..ca953e5f08 100644
--- a/src/network/core/core.c
+++ b/src/network/core/core.c
@@ -68,7 +68,7 @@ bool NetworkCoreInitialize(void)
 void NetworkCoreShutdown(void)
 {
 #if defined(__MORPHOS__) || defined(__AMIGA__)
-	/* free allocated ressources */
+	/* free allocated resources */
 #if defined(__AMIGA__)
 	if (TimerBase    != NULL) CloseDevice((struct IORequest*)TimerRequest); // XXX This smells wrong
 	if (TimerRequest != NULL) DeleteIORequest(TimerRequest);
diff --git a/src/network/core/os_abstraction.h b/src/network/core/os_abstraction.h
index 792c42658f..df3cf65b3f 100644
--- a/src/network/core/os_abstraction.h
+++ b/src/network/core/os_abstraction.h
@@ -150,7 +150,7 @@ typedef unsigned long in_addr_t;
 #	endif
 #endif // __MORPHOS__ || __AMIGA__
 
-static inline bool SetNonBlocking(int d)
+static inline bool SetNonBlocking(const int d)
 {
 #ifdef WIN32
 	u_long nonblocking = 1;
@@ -164,7 +164,7 @@ static inline bool SetNonBlocking(int d)
 #endif
 }
 
-static inline bool SetNoDelay(int d)
+static inline bool SetNoDelay(const int d)
 {
 	/* XXX should this be done at all? */
 #if !defined(BEOS_NET_SERVER) // not implemented on BeOS net_server
diff --git a/src/network/core/packet.c b/src/network/core/packet.c
index aed0b6299d..d75d78c7e1 100644
--- a/src/network/core/packet.c
+++ b/src/network/core/packet.c
@@ -22,7 +22,7 @@ extern void NORETURN CDECL error(const char *str, ...);
  * @param type the of packet
  * @return the newly created packet
  */
-Packet *NetworkSend_Init(PacketType type)
+Packet *NetworkSend_Init(const PacketType type)
 {
 	Packet *packet = malloc(sizeof(Packet));
 	/* An error is inplace here, because it simply means we ran out of memory. */
@@ -112,7 +112,7 @@ void NetworkSend_string(Packet *packet, const char* data)
 extern uint CloseConnection(NetworkClientState *cs);
 
 /** Is it safe to read from the packet, i.e. didn't we run over the buffer ? */
-static inline bool CanReadFromPacket(NetworkClientState *cs, Packet *packet, uint bytes_to_read)
+static inline bool CanReadFromPacket(NetworkClientState *cs, const Packet *packet, const uint bytes_to_read)
 {
 	/* Don't allow reading from a closed socket */
 	if (HasClientQuit(cs)) return false;
diff --git a/src/network/core/packet.h b/src/network/core/packet.h
index a44c6b50ec..e42c65d5c6 100644
--- a/src/network/core/packet.h
+++ b/src/network/core/packet.h
@@ -21,7 +21,7 @@ typedef struct NetworkClientState NetworkClientState;
  * @param cs the state to query
  * @param true if the connection should be considered dropped
  */
-bool HasClientQuit(NetworkClientState *cs);
+bool HasClientQuit(const NetworkClientState *cs);
 
 typedef uint16 PacketSize; ///< Size of the whole packet.
 typedef uint8  PacketType; ///< Identifier for the packet
@@ -49,7 +49,7 @@ typedef struct Packet {
 } Packet;
 
 
-Packet *NetworkSend_Init(PacketType type);
+Packet *NetworkSend_Init(const PacketType type);
 void NetworkSend_FillPacketSize(Packet *packet);
 void NetworkSend_uint8 (Packet *packet, uint8 data);
 void NetworkSend_uint16(Packet *packet, uint16 data);
diff --git a/src/network/core/tcp.c b/src/network/core/tcp.c
index 807288a86d..9261ea0496 100644
--- a/src/network/core/tcp.c
+++ b/src/network/core/tcp.c
@@ -46,7 +46,7 @@ NetworkRecvStatus CloseConnection(NetworkClientState *cs)
  * @param cs the client to check
  * @return true if the client has quit
  */
-bool HasClientQuit(NetworkClientState *cs)
+bool HasClientQuit(const NetworkClientState *cs)
 {
 	return cs->has_quit;
 }
diff --git a/src/network/core/udp.c b/src/network/core/udp.c
index 93c24a1561..72d600157d 100644
--- a/src/network/core/udp.c
+++ b/src/network/core/udp.c
@@ -20,7 +20,7 @@
  * @param broadcast whether to allow broadcast sending/receiving
  * @return true if the listening succeeded
  */
-bool NetworkUDPListen(SOCKET *udp, uint32 host, uint16 port, bool broadcast)
+bool NetworkUDPListen(SOCKET *udp, const uint32 host, const uint16 port, const bool broadcast)
 {
 	struct sockaddr_in sin;
 
@@ -85,7 +85,7 @@ void NetworkUDPClose(SOCKET *udp)
  * @param p    the packet to send
  * @param recv the receiver (target) of the packet
  */
-void NetworkSendUDP_Packet(SOCKET udp, Packet *p, struct sockaddr_in *recv)
+void NetworkSendUDP_Packet(const SOCKET udp, Packet *p, const struct sockaddr_in *recv)
 {
 	int res;
 
@@ -102,7 +102,7 @@ void NetworkSendUDP_Packet(SOCKET udp, Packet *p, struct sockaddr_in *recv)
  * Receive a packet at UDP level
  * @param udp the socket to receive the packet on
  */
-void NetworkUDPReceive(SOCKET udp)
+void NetworkUDPReceive(const SOCKET udp)
 {
 	struct sockaddr_in client_addr;
 	socklen_t client_len;
diff --git a/src/network/core/udp.h b/src/network/core/udp.h
index ce8b0e88f6..f0d4ed9832 100644
--- a/src/network/core/udp.h
+++ b/src/network/core/udp.h
@@ -16,11 +16,11 @@
 
 ///** Sending/receiving of UDP packets **////
 
-bool NetworkUDPListen(SOCKET *udp, uint32 host, uint16 port, bool broadcast);
+bool NetworkUDPListen(SOCKET *udp, const uint32 host, const uint16 port, const bool broadcast);
 void NetworkUDPClose(SOCKET *udp);
 
-void NetworkSendUDP_Packet(SOCKET udp, Packet *p, struct sockaddr_in *recv);
-void NetworkUDPReceive(SOCKET udp);
+void NetworkSendUDP_Packet(const SOCKET udp, Packet *p, const struct sockaddr_in *recv);
+void NetworkUDPReceive(const SOCKET udp);
 
 /**
  * Function that is called for every received UDP packet.
@@ -28,7 +28,7 @@ void NetworkUDPReceive(SOCKET udp);
  * @param packet      the received packet
  * @param client_addr the address of the sender of the packet
  */
-void NetworkHandleUDPPacket(SOCKET udp, Packet *p, struct sockaddr_in *client_addr);
+void NetworkHandleUDPPacket(const SOCKET udp, Packet *p, const struct sockaddr_in *client_addr);
 
 
 ///** Sending/receiving of (large) chuncks of UDP packets **////
diff --git a/src/network/network_udp.c b/src/network/network_udp.c
index f64ebc2b92..5caec3b423 100644
--- a/src/network/network_udp.c
+++ b/src/network/network_udp.c
@@ -28,7 +28,7 @@ enum {
 	ADVERTISE_RETRY_TIMES     =     3  // give up readvertising after this much failed retries
 };
 
-#define DEF_UDP_RECEIVE_COMMAND(type) void NetworkPacketReceive_ ## type ## _command(Packet *p, struct sockaddr_in *client_addr)
+#define DEF_UDP_RECEIVE_COMMAND(type) void NetworkPacketReceive_ ## type ## _command(Packet *p, const struct sockaddr_in *client_addr)
 
 static NetworkClientState _udp_cs;
 
@@ -403,7 +403,7 @@ DEF_UDP_RECEIVE_COMMAND(PACKET_UDP_SERVER_NEWGRFS)
  * game information of some 'random' host.
  */
 typedef struct NetworkUDPPacketAndSocket {
-	void (*callback)(Packet *p, struct sockaddr_in *client_addr);
+	void (*callback)(Packet *p, const struct sockaddr_in *client_addr);
 	SOCKET *incoming_socket;
 } NetworkUPDPacketAndSocket;
 
@@ -421,7 +421,7 @@ static const NetworkUPDPacketAndSocket _network_udp_packet[PACKET_UDP_END] = {
 	{ RECEIVE_COMMAND(PACKET_UDP_SERVER_NEWGRFS),       &_udp_client_socket },
 };
 
-void NetworkHandleUDPPacket(SOCKET udp, Packet *p, struct sockaddr_in *client_addr)
+void NetworkHandleUDPPacket(const SOCKET udp, Packet *p, const struct sockaddr_in *client_addr)
 {
 	byte type;