diff --git a/src/main.cpp b/src/main.cpp
index df93062..2a60081 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -7,13 +7,16 @@ int main(int argc, char **argv) {
     app.require_subcommand();
 
     CLI::App *search = app.add_subcommand("search", "Search for Profinet devices on the network.");
-    CLI::Option *interface = search->add_option("-i,--interface", "Interface to use");
+    std::string interfaceName;
+    CLI::Option *interface = search->add_option("-i,--interface", interfaceName, "Interface to use");
     int timeout = 1000;
     search->add_option("-t,--timeout", timeout, "Time to search for devices in milliseconds");
 
     CLI::App *configure = app.add_subcommand("configure", "Configure Profinet devices on the network.");
     CLI::Option *device = configure->add_option("device", "The current name of the device to configure. Use EMPTY for blank string.")
             ->required(true);
+    std::string configureInterfaceName;
+    configure->add_option("-I,--interface", configureInterfaceName, "Interface to use");
     configure->add_option("-t,--timeout", timeout, "Time to search for devices in milliseconds");
 
     std::string newName;
@@ -33,11 +36,10 @@ int main(int argc, char **argv) {
 
     try {
         if (*search) {
-            ProfinetTool profinetTool(timeout);
-            if (!interface->empty()) profinetTool = ProfinetTool(interface->as<std::string>(), timeout);
+            ProfinetTool profinetTool = interface->empty() ? ProfinetTool(timeout) : ProfinetTool(interfaceName, timeout);
             profinetTool.searchForDevices();
         } else if (*configure) {
-            ProfinetTool profinetTool(timeout);
+            ProfinetTool profinetTool = configureInterfaceName.empty() ? ProfinetTool(timeout) : ProfinetTool(configureInterfaceName, timeout);
             profinetTool.configureDevices(deviceName, newName, newIP, newSubnet,
                                           newGateway);
         }
@@ -46,6 +48,5 @@ int main(int argc, char **argv) {
         return EXIT_FAILURE;
     }
 
-
     return 0;
 }
diff --git a/src/pcapInterface.c b/src/pcapInterface.c
index dcab613..d0c17ad 100644
--- a/src/pcapInterface.c
+++ b/src/pcapInterface.c
@@ -87,14 +87,24 @@ void profinet_pcap_callback(unsigned char *args, const struct pcap_pkthdr *packe
     struct ether_header header;
     memcpy(&header, packet, sizeof(header));
 
-    if (header.ether_type != htons(ETH_P_8021Q)) return;
-
     const int packetLength = packetInfo->len;
+    int payloadOffset;
+
+    if (header.ether_type == htons(ETH_P_8021Q)) {
+        /* 802.1Q tagged frame: 4-byte VLAN tag after Ethernet header */
+        payloadOffset = (int) sizeof(struct ether_header) + 4;
+    } else if (header.ether_type == htons(0x8892)) {
+        /* Untagged Profinet frame */
+        payloadOffset = (int) sizeof(struct ether_header);
+    } else {
+        return;
+    }
 
-    const int profinetPacketSize = packetLength - (int) sizeof(struct ether_header) - 4;
+    const int profinetPacketSize = packetLength - payloadOffset;
+    if (profinetPacketSize <= 0) return;
 
     unsigned char profinetPacketRaw[profinetPacketSize];
-    memcpy(profinetPacketRaw, packet + sizeof(struct ether_header) + 4, profinetPacketSize);
+    memcpy(profinetPacketRaw, packet + payloadOffset, profinetPacketSize);
 
     struct profinet_dcp_header dcpHeader;
     memcpy(&dcpHeader, profinetPacketRaw, sizeof(dcpHeader));