diff --git a/tc.c b/tc.c
index 6f266d7..deb379c 100644
--- a/tc.c
+++ b/tc.c
@@ -55,10 +55,14 @@ void tc_block_all()
 void tc_allow_mac(const uint8_t mac[])
 {
     char cmd[2048];
+    char mac32[9];
+    char mac16[5];
+    snprintf(mac32, 9, "%2x%2x%2x%2x", mac[0], mac[1], mac[2], mac[3]);
+    snprintf(mac16, 5, "%2x%2x", mac[4], mac[5]);
     snprintf(cmd, 2048, "tc filter add dev %s protocol all parent ffff: prio 99 "
-             "basic match \"u32(u32 0x%2x%2x%2x%2x 0xffffffff at -8)\" "
-             "and \"u32(u16 0x%2x%2x 0xffff at -4)\" flowid :1 action pass",
-             g_interface, mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
+             "basic match \"u32(u32 0x%s 0x%s at -8)\" "
+             "and \"u32(u16 0x%s 0x%s at -4)\" flowid :1 action pass",
+             g_interface, mac32, mac32, mac16, mac16);
     log_debug("CMD: %s\n", cmd);
     system(cmd);
 }
@@ -66,10 +70,14 @@ void tc_allow_mac(const uint8_t mac[])
 void tc_disallow_mac(const uint8_t mac[])
 {
     char cmd[2048];
+    char mac32[9];
+    char mac16[5];
+    snprintf(mac32, 9, "%2x%2x%2x%2x", mac[0], mac[1], mac[2], mac[3]);
+    snprintf(mac16, 5, "%2x%2x", mac[4], mac[5]);
     snprintf(cmd, 2048, "tc filter delete dev %s protocol all parent ffff: prio 99 "
-             "basic match \"u32(u32 0x%2x%2x%2x%2x 0xffffffff at -8)\" "
-             "and \"u32(u16 0x%2x%2x 0xffff at -4)\" flowid :1 action pass",
-             g_interface, mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
+             "basic match \"u32(u32 0x%s 0x%s at -8)\" "
+             "and \"u32(u16 0x%s 0x%s at -4)\" flowid :1 action pass",
+             g_interface, mac32, mac32, mac16, mac16);
     log_debug("CMD: %s\n", cmd);
     system(cmd);
 }