diff --git a/ChangeLog b/ChangeLog
index 0edbd1605..6ba45ea08 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -92,6 +92,7 @@ API Changes
      in config.h
    * net_connect() and net_bind() have a new 'proto' argument to choose
      between TCP and UDP, using the macros NET_PROTO_TCP or NET_PROTO_UDP.
+     Their 'port' argument type is changed to a string.
    * Some constness fixes
 
 Removals
diff --git a/include/mbedtls/net.h b/include/mbedtls/net.h
index 586bd34ab..ed2d5d322 100644
--- a/include/mbedtls/net.h
+++ b/include/mbedtls/net.h
@@ -70,7 +70,7 @@ extern "C" {
  *
  * \note           Sets the socket in connected mode even with UDP.
  */
-int mbedtls_net_connect( int *fd, const char *host, int port, int proto );
+int mbedtls_net_connect( int *fd, const char *host, const char *port, int proto );
 
 /**
  * \brief          Create a receiving socket on bind_ip:port in the chosen
@@ -89,7 +89,7 @@ int mbedtls_net_connect( int *fd, const char *host, int port, int proto );
  * \note           Regardless of the protocol, opens the sockets and binds it.
  *                 In addition, make the socket listening if protocol is TCP.
  */
-int mbedtls_net_bind( int *fd, const char *bind_ip, int port, int proto );
+int mbedtls_net_bind( int *fd, const char *bind_ip, const char *port, int proto );
 
 /**
  * \brief           Accept a connection from a remote client
diff --git a/library/net.c b/library/net.c
index 8dd4c0965..f284153a9 100644
--- a/library/net.c
+++ b/library/net.c
@@ -86,12 +86,6 @@ typedef UINT32 uint32_t;
 #include <stdint.h>
 #endif
 
-#if defined(MBEDTLS_PLATFORM_C)
-#include "mbedtls/platform.h"
-#else
-#define mbedtls_snprintf snprintf
-#endif
-
 /*
  * Prepare for using the sockets interface
  */
@@ -119,26 +113,21 @@ static int net_prepare( void )
 /*
  * Initiate a TCP connection with host:port and the given protocol
  */
-int mbedtls_net_connect( int *fd, const char *host, int port, int proto )
+int mbedtls_net_connect( int *fd, const char *host, const char *port, int proto )
 {
     int ret;
     struct addrinfo hints, *addr_list, *cur;
-    char port_str[6];
 
     if( ( ret = net_prepare() ) != 0 )
         return( ret );
 
-    /* getaddrinfo expects port as a string */
-    memset( port_str, 0, sizeof( port_str ) );
-    mbedtls_snprintf( port_str, sizeof( port_str ), "%d", port );
-
     /* Do name resolution with both IPv6 and IPv4 */
     memset( &hints, 0, sizeof( hints ) );
     hints.ai_family = AF_UNSPEC;
     hints.ai_socktype = proto == MBEDTLS_NET_PROTO_UDP ? SOCK_DGRAM : SOCK_STREAM;
     hints.ai_protocol = proto == MBEDTLS_NET_PROTO_UDP ? IPPROTO_UDP : IPPROTO_TCP;
 
-    if( getaddrinfo( host, port_str, &hints, &addr_list ) != 0 )
+    if( getaddrinfo( host, port, &hints, &addr_list ) != 0 )
         return( MBEDTLS_ERR_NET_UNKNOWN_HOST );
 
     /* Try the sockaddrs until a connection succeeds */
@@ -171,19 +160,14 @@ int mbedtls_net_connect( int *fd, const char *host, int port, int proto )
 /*
  * Create a listening socket on bind_ip:port
  */
-int mbedtls_net_bind( int *fd, const char *bind_ip, int port, int proto )
+int mbedtls_net_bind( int *fd, const char *bind_ip, const char *port, int proto )
 {
     int n, ret;
     struct addrinfo hints, *addr_list, *cur;
-    char port_str[6];
 
     if( ( ret = net_prepare() ) != 0 )
         return( ret );
 
-    /* getaddrinfo expects port as a string */
-    memset( port_str, 0, sizeof( port_str ) );
-    mbedtls_snprintf( port_str, sizeof( port_str ), "%d", port );
-
     /* Bind to IPv6 and/or IPv4, but only in TCP */
     memset( &hints, 0, sizeof( hints ) );
     hints.ai_family = AF_UNSPEC;
@@ -192,7 +176,7 @@ int mbedtls_net_bind( int *fd, const char *bind_ip, int port, int proto )
     if( bind_ip == NULL )
         hints.ai_flags = AI_PASSIVE;
 
-    if( getaddrinfo( bind_ip, port_str, &hints, &addr_list ) != 0 )
+    if( getaddrinfo( bind_ip, port, &hints, &addr_list ) != 0 )
         return( MBEDTLS_ERR_NET_UNKNOWN_HOST );
 
     /* Try the sockaddrs until a binding succeeds */
diff --git a/programs/pkey/dh_client.c b/programs/pkey/dh_client.c
index 0b340d516..e9523ce84 100644
--- a/programs/pkey/dh_client.c
+++ b/programs/pkey/dh_client.c
@@ -50,7 +50,7 @@
 #endif
 
 #define SERVER_NAME "localhost"
-#define SERVER_PORT 11999
+#define SERVER_PORT "11999"
 
 #if !defined(MBEDTLS_AES_C) || !defined(MBEDTLS_DHM_C) ||     \
     !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_NET_C) ||  \
@@ -134,7 +134,7 @@ int main( void )
     /*
      * 3. Initiate the connection
      */
-    mbedtls_printf( "\n  . Connecting to tcp/%s/%d", SERVER_NAME,
+    mbedtls_printf( "\n  . Connecting to tcp/%s/%s", SERVER_NAME,
                                              SERVER_PORT );
     fflush( stdout );
 
diff --git a/programs/pkey/dh_server.c b/programs/pkey/dh_server.c
index 8fda29fda..30abaa894 100644
--- a/programs/pkey/dh_server.c
+++ b/programs/pkey/dh_server.c
@@ -49,7 +49,7 @@
 #include <string.h>
 #endif
 
-#define SERVER_PORT 11999
+#define SERVER_PORT "11999"
 #define PLAINTEXT "==Hello there!=="
 
 #if !defined(MBEDTLS_AES_C) || !defined(MBEDTLS_DHM_C) ||     \
diff --git a/programs/ssl/dtls_client.c b/programs/ssl/dtls_client.c
index cc0d051bb..6ac83d7bd 100644
--- a/programs/ssl/dtls_client.c
+++ b/programs/ssl/dtls_client.c
@@ -61,7 +61,7 @@ int main( void )
 #include "mbedtls/certs.h"
 #include "mbedtls/timing.h"
 
-#define SERVER_PORT 4433
+#define SERVER_PORT "4433"
 #define SERVER_NAME "localhost"
 #define SERVER_ADDR "127.0.0.1" /* forces IPv4 */
 #define MESSAGE     "Echo this"
@@ -142,8 +142,7 @@ int main( int argc, char *argv[] )
     /*
      * 1. Start the connection
      */
-    mbedtls_printf( "  . Connecting to udp/%s/%4d...", SERVER_NAME,
-                                               SERVER_PORT );
+    mbedtls_printf( "  . Connecting to udp/%s/%s...", SERVER_NAME, SERVER_PORT );
     fflush( stdout );
 
     if( ( ret = mbedtls_net_connect( &server_fd, SERVER_ADDR,
diff --git a/programs/ssl/dtls_server.c b/programs/ssl/dtls_server.c
index 3ad10ceec..69da1d381 100644
--- a/programs/ssl/dtls_server.c
+++ b/programs/ssl/dtls_server.c
@@ -167,7 +167,7 @@ int main( void )
     printf( "  . Bind on udp/*/4433 ..." );
     fflush( stdout );
 
-    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, 4433, MBEDTLS_NET_PROTO_UDP ) ) != 0 )
+    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, "4433", MBEDTLS_NET_PROTO_UDP ) ) != 0 )
     {
         printf( " failed\n  ! mbedtls_net_bind returned %d\n\n", ret );
         goto exit;
@@ -274,7 +274,7 @@ reset:
     }
 
     /* With UDP, bind_fd is hijacked by client_fd, so bind a new one */
-    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, 4433, MBEDTLS_NET_PROTO_UDP ) ) != 0 )
+    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, "4433", MBEDTLS_NET_PROTO_UDP ) ) != 0 )
     {
         printf( " failed\n  ! mbedtls_net_bind returned -0x%x\n\n", -ret );
         goto exit;
diff --git a/programs/ssl/ssl_client1.c b/programs/ssl/ssl_client1.c
index b67230514..c1da0a2ea 100644
--- a/programs/ssl/ssl_client1.c
+++ b/programs/ssl/ssl_client1.c
@@ -60,7 +60,7 @@ int main( void )
 
 #include <string.h>
 
-#define SERVER_PORT 4433
+#define SERVER_PORT "4433"
 #define SERVER_NAME "localhost"
 #define GET_REQUEST "GET / HTTP/1.0\r\n\r\n"
 
@@ -132,8 +132,7 @@ int main( void )
     /*
      * 1. Start the connection
      */
-    mbedtls_printf( "  . Connecting to tcp/%s/%4d...", SERVER_NAME,
-                                               SERVER_PORT );
+    mbedtls_printf( "  . Connecting to tcp/%s/%s...", SERVER_NAME, SERVER_PORT );
     fflush( stdout );
 
     if( ( ret = mbedtls_net_connect( &server_fd, SERVER_NAME,
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index b8a4a628d..b24d70437 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -70,7 +70,7 @@ int main( void )
 
 #define DFL_SERVER_NAME         "localhost"
 #define DFL_SERVER_ADDR         NULL
-#define DFL_SERVER_PORT         4433
+#define DFL_SERVER_PORT         "4433"
 #define DFL_REQUEST_PAGE        "/"
 #define DFL_REQUEST_SIZE        -1
 #define DFL_DEBUG_LEVEL         0
@@ -272,7 +272,7 @@ struct options
 {
     const char *server_name;    /* hostname of the server (client only)     */
     const char *server_addr;    /* address of the server (client only)      */
-    int server_port;            /* port on which the ssl service runs       */
+    const char *server_port;    /* port on which the ssl service runs       */
     int debug_level;            /* level of debugging                       */
     int nbio;                   /* should I/O be blocking?                  */
     uint32_t read_timeout;      /* timeout on mbedtls_ssl_read() in milliseconds    */
@@ -502,11 +502,7 @@ int main( int argc, char *argv[] )
         else if( strcmp( p, "server_addr" ) == 0 )
             opt.server_addr = q;
         else if( strcmp( p, "server_port" ) == 0 )
-        {
-            opt.server_port = atoi( q );
-            if( opt.server_port < 1 || opt.server_port > 65535 )
-                goto usage;
-        }
+            opt.server_port = q;
         else if( strcmp( p, "dtls" ) == 0 )
         {
             int t = atoi( q );
@@ -1026,7 +1022,7 @@ int main( int argc, char *argv[] )
     if( opt.server_addr == NULL)
         opt.server_addr = opt.server_name;
 
-    mbedtls_printf( "  . Connecting to %s/%s/%-4d...",
+    mbedtls_printf( "  . Connecting to %s/%s/%s...",
             opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ? "tcp" : "udp",
             opt.server_addr, opt.server_port );
     fflush( stdout );
diff --git a/programs/ssl/ssl_fork_server.c b/programs/ssl/ssl_fork_server.c
index bafaa01f6..26855a2d3 100644
--- a/programs/ssl/ssl_fork_server.c
+++ b/programs/ssl/ssl_fork_server.c
@@ -202,7 +202,7 @@ int main( void )
     mbedtls_printf( "  . Bind on https://localhost:4433/ ..." );
     fflush( stdout );
 
-    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, 4433, MBEDTLS_NET_PROTO_TCP ) ) != 0 )
+    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, "4433", MBEDTLS_NET_PROTO_TCP ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_net_bind returned %d\n\n", ret );
         goto exit;
diff --git a/programs/ssl/ssl_mail_client.c b/programs/ssl/ssl_mail_client.c
index c06d0c06d..f16eb8731 100644
--- a/programs/ssl/ssl_mail_client.c
+++ b/programs/ssl/ssl_mail_client.c
@@ -84,7 +84,7 @@ int main( void )
 #endif
 
 #define DFL_SERVER_NAME         "localhost"
-#define DFL_SERVER_PORT         465
+#define DFL_SERVER_PORT         "465"
 #define DFL_USER_NAME           "user"
 #define DFL_USER_PWD            "password"
 #define DFL_MAIL_FROM           ""
@@ -140,7 +140,7 @@ int main( void )
 struct options
 {
     const char *server_name;    /* hostname of the server (client only)     */
-    int server_port;            /* port on which the ssl service runs       */
+    const char *server_port;    /* port on which the ssl service runs       */
     int debug_level;            /* level of debugging                       */
     int authentication;         /* if authentication is required            */
     int mode;                   /* SSL/TLS (0) or STARTTLS (1)              */
@@ -416,11 +416,7 @@ int main( int argc, char *argv[] )
         if( strcmp( p, "server_name" ) == 0 )
             opt.server_name = q;
         else if( strcmp( p, "server_port" ) == 0 )
-        {
-            opt.server_port = atoi( q );
-            if( opt.server_port < 1 || opt.server_port > 65535 )
-                goto usage;
-        }
+            opt.server_port = q;
         else if( strcmp( p, "debug_level" ) == 0 )
         {
             opt.debug_level = atoi( q );
@@ -566,7 +562,7 @@ int main( int argc, char *argv[] )
     /*
      * 2. Start the connection
      */
-    mbedtls_printf( "  . Connecting to tcp/%s/%-4d...", opt.server_name,
+    mbedtls_printf( "  . Connecting to tcp/%s/%s...", opt.server_name,
                                                 opt.server_port );
     fflush( stdout );
 
diff --git a/programs/ssl/ssl_pthread_server.c b/programs/ssl/ssl_pthread_server.c
index 3af66d045..3a137e315 100644
--- a/programs/ssl/ssl_pthread_server.c
+++ b/programs/ssl/ssl_pthread_server.c
@@ -448,7 +448,7 @@ int main( void )
     mbedtls_printf( "  . Bind on https://localhost:4433/ ..." );
     fflush( stdout );
 
-    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, 4433, MBEDTLS_NET_PROTO_TCP ) ) != 0 )
+    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, "4433", MBEDTLS_NET_PROTO_TCP ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_net_bind returned %d\n\n", ret );
         goto exit;
diff --git a/programs/ssl/ssl_server.c b/programs/ssl/ssl_server.c
index f2f969c2d..6535ec9f4 100644
--- a/programs/ssl/ssl_server.c
+++ b/programs/ssl/ssl_server.c
@@ -161,7 +161,7 @@ int main( void )
     mbedtls_printf( "  . Bind on https://localhost:4433/ ..." );
     fflush( stdout );
 
-    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, 4433, MBEDTLS_NET_PROTO_TCP ) ) != 0 )
+    if( ( ret = mbedtls_net_bind( &listen_fd, NULL, "4433", MBEDTLS_NET_PROTO_TCP ) ) != 0 )
     {
         mbedtls_printf( " failed\n  ! mbedtls_net_bind returned %d\n\n", ret );
         goto exit;
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index 6ac24068d..763cccf60 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -91,7 +91,7 @@ int main( void )
 #endif
 
 #define DFL_SERVER_ADDR         NULL
-#define DFL_SERVER_PORT         4433
+#define DFL_SERVER_PORT         "4433"
 #define DFL_DEBUG_LEVEL         0
 #define DFL_NBIO                0
 #define DFL_READ_TIMEOUT        0
@@ -346,7 +346,7 @@ int main( void )
 struct options
 {
     const char *server_addr;    /* address on which the ssl service runs    */
-    int server_port;            /* port on which the ssl service runs       */
+    const char *server_port;    /* port on which the ssl service runs       */
     int debug_level;            /* level of debugging                       */
     int nbio;                   /* should I/O be blocking?                  */
     uint32_t read_timeout;      /* timeout on mbedtls_ssl_read() in milliseconds    */
@@ -931,11 +931,7 @@ int main( int argc, char *argv[] )
         *q++ = '\0';
 
         if( strcmp( p, "server_port" ) == 0 )
-        {
-            opt.server_port = atoi( q );
-            if( opt.server_port < 1 || opt.server_port > 65535 )
-                goto usage;
-        }
+            opt.server_port = q;
         else if( strcmp( p, "server_addr" ) == 0 )
             opt.server_addr = q;
         else if( strcmp( p, "dtls" ) == 0 )
@@ -1558,7 +1554,7 @@ int main( int argc, char *argv[] )
     /*
      * 2. Setup the listening TCP socket
      */
-    mbedtls_printf( "  . Bind on %s://%s:%-4d/ ...",
+    mbedtls_printf( "  . Bind on %s://%s:%s/ ...",
             opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ? "tcp" : "udp",
             opt.server_addr ? opt.server_addr : "*",
             opt.server_port );
@@ -1906,7 +1902,7 @@ reset:
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( opt.transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
     {
-        mbedtls_printf( "  . Re-bind on udp://%s:%-4d/ ...",
+        mbedtls_printf( "  . Re-bind on udp://%s:%s/ ...",
                 opt.server_addr ? opt.server_addr : "*",
                 opt.server_port );
         fflush( stdout );
diff --git a/programs/test/udp_proxy.c b/programs/test/udp_proxy.c
index 04dded3cc..f91d42f1d 100644
--- a/programs/test/udp_proxy.c
+++ b/programs/test/udp_proxy.c
@@ -76,9 +76,9 @@ int main( void )
 #define MAX_MSG_SIZE            16384 + 2048 /* max record/datagram size */
 
 #define DFL_SERVER_ADDR         "localhost"
-#define DFL_SERVER_PORT         4433
+#define DFL_SERVER_PORT         "4433"
 #define DFL_LISTEN_ADDR         "localhost"
-#define DFL_LISTEN_PORT         5556
+#define DFL_LISTEN_PORT         "5556"
 
 #define USAGE                                                               \
     "\n usage: udp_proxy param=<>...\n"                                     \
@@ -110,9 +110,9 @@ int main( void )
 static struct options
 {
     const char *server_addr;    /* address to forward packets to            */
-    int server_port;            /* port to forward packets to               */
+    const char *server_port;    /* port to forward packets to               */
     const char *listen_addr;    /* address for accepting client connections */
-    int listen_port;            /* port for accepting client connections    */
+    const char *listen_port;    /* port for accepting client connections    */
 
     int duplicate;              /* duplicate 1 in N packets (none if 0)     */
     int delay;                  /* delay 1 packet in N (none if 0)          */
@@ -158,19 +158,11 @@ static void get_options( int argc, char *argv[] )
         if( strcmp( p, "server_addr" ) == 0 )
             opt.server_addr = q;
         else if( strcmp( p, "server_port" ) == 0 )
-        {
-            opt.server_port = atoi( q );
-            if( opt.server_port < 1 || opt.server_port > 65535 )
-                exit_usage( p, q );
-        }
+            opt.server_port = q;
         else if( strcmp( p, "listen_addr" ) == 0 )
             opt.listen_addr = q;
         else if( strcmp( p, "listen_port" ) == 0 )
-        {
-            opt.listen_port = atoi( q );
-            if( opt.listen_port < 1 || opt.listen_port > 65535 )
-                exit_usage( p, q );
-        }
+            opt.listen_port = q;
         else if( strcmp( p, "duplicate" ) == 0 )
         {
             opt.duplicate = atoi( q );
@@ -498,7 +490,7 @@ int main( int argc, char *argv[] )
     /*
      * 0. "Connect" to the server
      */
-    mbedtls_printf( "  . Connect to server on UDP/%s/%d ...",
+    mbedtls_printf( "  . Connect to server on UDP/%s/%s ...",
             opt.server_addr, opt.server_port );
     fflush( stdout );
 
@@ -514,7 +506,7 @@ int main( int argc, char *argv[] )
     /*
      * 1. Setup the "listening" UDP socket
      */
-    mbedtls_printf( "  . Bind on UDP/%s/%d ...",
+    mbedtls_printf( "  . Bind on UDP/%s/%s ...",
             opt.listen_addr, opt.listen_port );
     fflush( stdout );
 
@@ -544,7 +536,7 @@ accept:
     mbedtls_printf( " ok\n" );
     fflush( stdout );
 
-    mbedtls_printf( "  . Re-bind on UDP/%s/%d ...",
+    mbedtls_printf( "  . Re-bind on UDP/%s/%s ...",
             opt.listen_addr, opt.listen_port );
     fflush( stdout );
 
diff --git a/programs/x509/cert_app.c b/programs/x509/cert_app.c
index d93aeba17..bd5ccda98 100644
--- a/programs/x509/cert_app.c
+++ b/programs/x509/cert_app.c
@@ -70,7 +70,7 @@ int main( void )
 #define DFL_CRL_FILE            ""
 #define DFL_CA_PATH             ""
 #define DFL_SERVER_NAME         "localhost"
-#define DFL_SERVER_PORT         4433
+#define DFL_SERVER_PORT         "4433"
 #define DFL_DEBUG_LEVEL         0
 #define DFL_PERMISSIVE          0
 
@@ -105,7 +105,7 @@ struct options
     const char *crl_file;       /* the file with the CRL to use         */
     const char *ca_path;        /* the path with the CA certificate(s) reside */
     const char *server_name;    /* hostname of the server (client only) */
-    int server_port;            /* port on which the ssl service runs   */
+    const char *server_port;    /* port on which the ssl service runs   */
     int debug_level;            /* level of debugging                   */
     int permissive;             /* permissive parsing                   */
 } opt;
@@ -226,11 +226,7 @@ int main( int argc, char *argv[] )
         else if( strcmp( p, "server_name" ) == 0 )
             opt.server_name = q;
         else if( strcmp( p, "server_port" ) == 0 )
-        {
-            opt.server_port = atoi( q );
-            if( opt.server_port < 1 || opt.server_port > 65535 )
-                goto usage;
-        }
+            opt.server_port = q;
         else if( strcmp( p, "debug_level" ) == 0 )
         {
             opt.debug_level = atoi( q );
@@ -383,8 +379,8 @@ int main( int argc, char *argv[] )
         /*
          * 2. Start the connection
          */
-        mbedtls_printf( "  . SSL connection to tcp/%s/%-4d...", opt.server_name,
-                                                        opt.server_port );
+        mbedtls_printf( "  . SSL connection to tcp/%s/%s...", opt.server_name,
+                                                              opt.server_port );
         fflush( stdout );
 
         if( ( ret = mbedtls_net_connect( &server_fd, opt.server_name,