diff --git a/examples/dtls-echo/dtls-client.c b/examples/dtls-echo/dtls-client.c
index 63a8d76cc6..669e6b95c3 100644
--- a/examples/dtls-echo/dtls-client.c
+++ b/examples/dtls-echo/dtls-client.c
@@ -25,9 +25,12 @@
 
 #include "net/gnrc.h"
 #include "net/gnrc/ipv6.h"
+#include "net/gnrc/netif.h"
+#include "net/gnrc/netif/hdr.h"
 #include "net/gnrc/udp.h"
 #include "net/gnrc/pktdump.h"
 #include "timex.h"
+#include "utlist.h"
 #include "xtimer.h"
 
 #define ENABLE_DEBUG (0)
@@ -228,9 +231,15 @@ static int peer_verify_ecdsa_key(struct dtls_context_t *ctx,
  */
 static int gnrc_sending(char *addr_str, char *data, size_t data_len )
 {
+    int iface;
     ipv6_addr_t addr;
     gnrc_pktsnip_t *payload, *udp, *ip;
 
+    /* get interface, if available */
+    iface = ipv6_addr_split_iface(addr_str);
+    if ((iface < 0) && (gnrc_netif_numof() == 1)) {
+        iface = gnrc_netif_iter(NULL)->pid;
+    }
     /* parse destination address */
     if (ipv6_addr_from_str(&addr, addr_str) == NULL) {
         puts("Error: unable to parse destination address");
@@ -260,6 +269,13 @@ static int gnrc_sending(char *addr_str, char *data, size_t data_len )
         gnrc_pktbuf_release(udp);
         return -1;
     }
+    /* add netif header, if interface was given */
+    if (iface > 0) {
+        gnrc_pktsnip_t *netif = gnrc_netif_hdr_build(NULL, 0, NULL, 0);
+
+        ((gnrc_netif_hdr_t *)netif->data)->if_pid = (kernel_pid_t)iface;
+        LL_PREPEND(ip, netif);
+    }
 
     /*
      * WARNING: Too fast and the nodes dies in middle of retransmissions.
diff --git a/examples/dtls-echo/dtls-server.c b/examples/dtls-echo/dtls-server.c
index 0bbd58d8ab..083764b211 100644
--- a/examples/dtls-echo/dtls-server.c
+++ b/examples/dtls-echo/dtls-server.c
@@ -26,8 +26,11 @@
 
 #include "net/gnrc.h"
 #include "net/gnrc/ipv6.h"
+#include "net/gnrc/netif.h"
+#include "net/gnrc/netif/hdr.h"
 #include "net/gnrc/udp.h"
 #include "timex.h"
+#include "utlist.h"
 #include "xtimer.h"
 #include "msg.h"
 
@@ -142,10 +145,15 @@ static int read_from_peer(struct dtls_context_t *ctx,
  */
 static int gnrc_sending(char *addr_str, char *data, size_t data_len, unsigned short rem_port )
 {
-
+    int iface;
     ipv6_addr_t addr;
     gnrc_pktsnip_t *payload, *udp, *ip;
 
+    /* get interface, if available */
+    iface = ipv6_addr_split_iface(addr_str);
+    if ((iface < 0) && (gnrc_netif_numof() == 1)) {
+        iface = gnrc_netif_iter(NULL)->pid;
+    }
     /* parse destination address */
     if (ipv6_addr_from_str(&addr, addr_str) == NULL) {
         puts("Error: unable to parse destination address");
@@ -174,6 +182,13 @@ static int gnrc_sending(char *addr_str, char *data, size_t data_len, unsigned sh
         gnrc_pktbuf_release(udp);
         return -1;
     }
+    /* add netif header, if interface was given */
+    if (iface > 0) {
+        gnrc_pktsnip_t *netif = gnrc_netif_hdr_build(NULL, 0, NULL, 0);
+
+        ((gnrc_netif_hdr_t *)netif->data)->if_pid = (kernel_pid_t)iface;
+        LL_PREPEND(ip, netif);
+    }
     /* send packet */
 
     DEBUG("DBG-Server: Sending record to peer\n");
diff --git a/examples/gnrc_networking/udp.c b/examples/gnrc_networking/udp.c
index fcfb54e870..ada54e569e 100644
--- a/examples/gnrc_networking/udp.c
+++ b/examples/gnrc_networking/udp.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2015 Freie Universität Berlin
+ * Copyright (C) 2015-17 Freie Universität Berlin
  *
  * This file is subject to the terms and conditions of the GNU Lesser
  * General Public License v2.1. See the file LICENSE in the top level
@@ -14,6 +14,7 @@
  * @brief       Demonstrating the sending and receiving of UDP data
  *
  * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ * @author      Martine Lenders <m.lenders@fu-berlin.de>
  *
  * @}
  */
@@ -23,9 +24,12 @@
 
 #include "net/gnrc.h"
 #include "net/gnrc/ipv6.h"
+#include "net/gnrc/netif.h"
+#include "net/gnrc/netif/hdr.h"
 #include "net/gnrc/udp.h"
 #include "net/gnrc/pktdump.h"
 #include "timex.h"
+#include "utlist.h"
 #include "xtimer.h"
 
 static gnrc_netreg_entry_t server = GNRC_NETREG_ENTRY_INIT_PID(GNRC_NETREG_DEMUX_CTX_ALL,
@@ -35,9 +39,15 @@ static gnrc_netreg_entry_t server = GNRC_NETREG_ENTRY_INIT_PID(GNRC_NETREG_DEMUX
 static void send(char *addr_str, char *port_str, char *data, unsigned int num,
                  unsigned int delay)
 {
+    int iface;
     uint16_t port;
     ipv6_addr_t addr;
 
+    /* get interface, if available */
+    iface = ipv6_addr_split_iface(addr_str);
+    if ((iface < 0) && (gnrc_netif_numof() == 1)) {
+        iface = gnrc_netif_iter(NULL)->pid;
+    }
     /* parse destination address */
     if (ipv6_addr_from_str(&addr, addr_str) == NULL) {
         puts("Error: unable to parse destination address");
@@ -75,6 +85,13 @@ static void send(char *addr_str, char *port_str, char *data, unsigned int num,
             gnrc_pktbuf_release(udp);
             return;
         }
+        /* add netif header, if interface was given */
+        if (iface > 0) {
+            gnrc_pktsnip_t *netif = gnrc_netif_hdr_build(NULL, 0, NULL, 0);
+
+            ((gnrc_netif_hdr_t *)netif->data)->if_pid = (kernel_pid_t)iface;
+            LL_PREPEND(ip, netif);
+        }
         /* send packet */
         if (!gnrc_netapi_dispatch_send(GNRC_NETTYPE_UDP, GNRC_NETREG_DEMUX_CTX_ALL, ip)) {
             puts("Error: unable to locate UDP thread");
diff --git a/examples/gnrc_networking_mac/udp.c b/examples/gnrc_networking_mac/udp.c
index b3feccf973..cb6d16835d 100644
--- a/examples/gnrc_networking_mac/udp.c
+++ b/examples/gnrc_networking_mac/udp.c
@@ -23,9 +23,12 @@
 
 #include "net/gnrc.h"
 #include "net/gnrc/ipv6.h"
+#include "net/gnrc/netif.h"
+#include "net/gnrc/netif/hdr.h"
 #include "net/gnrc/udp.h"
 #include "net/gnrc/pktdump.h"
 #include "timex.h"
+#include "utlist.h"
 #include "xtimer.h"
 
 static gnrc_netreg_entry_t server = GNRC_NETREG_ENTRY_INIT_PID(GNRC_NETREG_DEMUX_CTX_ALL,
@@ -35,9 +38,15 @@ static gnrc_netreg_entry_t server = GNRC_NETREG_ENTRY_INIT_PID(GNRC_NETREG_DEMUX
 static void send(char *addr_str, char *port_str, char *data, unsigned int num,
                  unsigned int delay)
 {
+    int iface;
     uint16_t port;
     ipv6_addr_t addr;
 
+    /* get interface, if available */
+    iface = ipv6_addr_split_iface(addr_str);
+    if ((iface < 0) && (gnrc_netif_numof() == 1)) {
+        iface = gnrc_netif_iter(NULL)->pid;
+    }
     /* parse destination address */
     if (ipv6_addr_from_str(&addr, addr_str) == NULL) {
         puts("Error: unable to parse destination address");
@@ -75,6 +84,13 @@ static void send(char *addr_str, char *port_str, char *data, unsigned int num,
             gnrc_pktbuf_release(udp);
             return;
         }
+        /* add netif header, if interface was given */
+        if (iface > 0) {
+            gnrc_pktsnip_t *netif = gnrc_netif_hdr_build(NULL, 0, NULL, 0);
+
+            ((gnrc_netif_hdr_t *)netif->data)->if_pid = (kernel_pid_t)iface;
+            LL_PREPEND(ip, netif);
+        }
         /* send packet */
         if (!gnrc_netapi_dispatch_send(GNRC_NETTYPE_UDP, GNRC_NETREG_DEMUX_CTX_ALL, ip)) {
             puts("Error: unable to locate UDP thread");
diff --git a/tests/gnrc_udp/udp.c b/tests/gnrc_udp/udp.c
index 097d031c4e..e6db56537e 100644
--- a/tests/gnrc_udp/udp.c
+++ b/tests/gnrc_udp/udp.c
@@ -22,9 +22,12 @@
 #include "msg.h"
 #include "net/gnrc.h"
 #include "net/gnrc/ipv6.h"
+#include "net/gnrc/netif.h"
+#include "net/gnrc/netif/hdr.h"
 #include "net/gnrc/udp.h"
 #include "net/gnrc/pktdump.h"
 #include "timex.h"
+#include "utlist.h"
 #include "xtimer.h"
 
 #define SERVER_MSG_QUEUE_SIZE   (8U)
@@ -78,10 +81,16 @@ static void *_eventloop(void *arg)
 static void send(char *addr_str, char *port_str, char *data_len_str, unsigned int num,
                  unsigned int delay)
 {
+    int iface;
     uint16_t port;
     ipv6_addr_t addr;
     size_t data_len;
 
+    /* get interface, if available */
+    iface = ipv6_addr_split_iface(addr_str);
+    if ((iface < 0) && (gnrc_netif_numof() == 1)) {
+        iface = gnrc_netif_iter(NULL)->pid;
+    }
     /* parse destination address */
     if (ipv6_addr_from_str(&addr, addr_str) == NULL) {
         puts("Error: unable to parse destination address");
@@ -123,6 +132,13 @@ static void send(char *addr_str, char *port_str, char *data_len_str, unsigned in
             gnrc_pktbuf_release(udp);
             return;
         }
+        /* add netif header, if interface was given */
+        if (iface > 0) {
+            gnrc_pktsnip_t *netif = gnrc_netif_hdr_build(NULL, 0, NULL, 0);
+
+            ((gnrc_netif_hdr_t *)netif->data)->if_pid = (kernel_pid_t)iface;
+            LL_PREPEND(ip, netif);
+        }
         /* send packet */
         if (!gnrc_netapi_dispatch_send(GNRC_NETTYPE_UDP, GNRC_NETREG_DEMUX_CTX_ALL, ip)) {
             puts("Error: unable to locate UDP thread");