diff --git a/other/DHT_bootstrap.c b/other/DHT_bootstrap.c
index 795e24ac..099aad80 100644
--- a/other/DHT_bootstrap.c
+++ b/other/DHT_bootstrap.c
@@ -89,33 +89,9 @@ int main(int argc, char *argv[])
 
     /* let user override default by cmdline */
     uint8_t ipv6enabled = TOX_ENABLE_IPV6_DEFAULT; /* x */
-
-    int argvoffset = 0, argi;
-    for(argi = 1; argi < argc; argi++)
-        if (!strncasecmp(argv[argi], "--ipv", 5)) {
-            if (argv[argi][5] && !argv[argi][6]) {
-                char c = argv[argi][5];
-                if (c == '4')
-                    ipv6enabled = 0;
-                else if (c == '6')
-                    ipv6enabled = 1;
-                else {
-                    printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                    exit(1);
-                }
-            }
-            else {
-                printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                exit(1);
-            }
-
-            if (argvoffset != argi - 1) {
-                printf("Argument must come first: %s.\n", argv[argi]);
-                exit(1);
-            }
-
-            argvoffset++;
-        }
+    int argvoffset = cmdline_parsefor_ipv46(argc, argv, &ipv6enabled);
+    if (argvoffset < 0)
+        exit(1);
 
     /* Initialize networking -
        Bind to ip 0.0.0.0 / [::] : PORT */
diff --git a/testing/DHT_test.c b/testing/DHT_test.c
index 61762162..ba8c2f23 100644
--- a/testing/DHT_test.c
+++ b/testing/DHT_test.c
@@ -140,33 +140,9 @@ int main(int argc, char *argv[])
 
     /* let user override default by cmdline */
     uint8_t ipv6enabled = TOX_ENABLE_IPV6_DEFAULT; /* x */
-
-    int argvoffset = 0, argi;
-    for(argi = 1; argi < argc; argi++)
-        if (!strncasecmp(argv[argi], "--ipv", 5)) {
-            if (argv[argi][5] && !argv[argi][6]) {
-                char c = argv[argi][5];
-                if (c == '4')
-                    ipv6enabled = 0;
-                else if (c == '6')
-                    ipv6enabled = 1;
-                else {
-                    printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                    exit(1);
-                }
-            }
-            else {
-                printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                exit(1);
-            }
-
-            if (argvoffset != argi - 1) {
-                printf("Argument must come first: %s.\n", argv[argi]);
-                exit(1);
-            }
-
-            argvoffset++;
-        }
+    int argvoffset = cmdline_parsefor_ipv46(argc, argv, &ipv6enabled);
+    if (argvoffset < 0)
+        exit(1);
 
     //memcpy(self_client_id, "qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq", 32);
     /* initialize networking */
diff --git a/testing/Lossless_UDP_testclient.c b/testing/Lossless_UDP_testclient.c
index 5d4c8547..70349204 100644
--- a/testing/Lossless_UDP_testclient.c
+++ b/testing/Lossless_UDP_testclient.c
@@ -153,33 +153,9 @@ int main(int argc, char *argv[])
 {
     /* let user override default by cmdline */
     uint8_t ipv6enabled = TOX_ENABLE_IPV6_DEFAULT; /* x */
-
-    int argvoffset = 0, argi;
-    for(argi = 1; argi < argc; argi++)
-        if (!strncasecmp(argv[argi], "--ipv", 5)) {
-            if (argv[argi][5] && !argv[argi][6]) {
-                char c = argv[argi][5];
-                if (c == '4')
-                    ipv6enabled = 0;
-                else if (c == '6')
-                    ipv6enabled = 1;
-                else {
-                    printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                    exit(1);
-                }
-            }
-            else {
-                printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                exit(1);
-            }
-
-            if (argvoffset != argi - 1) {
-                printf("Argument must come first: %s.\n", argv[argi]);
-                exit(1);
-            }
-
-            argvoffset++;
-        }
+    int argvoffset = cmdline_parsefor_ipv46(argc, argv, &ipv6enabled);
+    if (argvoffset < 0)
+        exit(1);
 
     if (argc < argvoffset + 4) {
         printf("Usage: %s [--ipv4|--ipv6] ip port filename\n", argv[0]);
diff --git a/testing/Lossless_UDP_testserver.c b/testing/Lossless_UDP_testserver.c
index 52dbcc80..343a662a 100644
--- a/testing/Lossless_UDP_testserver.c
+++ b/testing/Lossless_UDP_testserver.c
@@ -149,33 +149,9 @@ int main(int argc, char *argv[])
 {
     /* let user override default by cmdline */
     uint8_t ipv6enabled = TOX_ENABLE_IPV6_DEFAULT; /* x */
-
-    int argvoffset = 0, argi;
-    for(argi = 1; argi < argc; argi++)
-        if (!strncasecmp(argv[argi], "--ipv", 5)) {
-            if (argv[argi][5] && !argv[argi][6]) {
-                char c = argv[argi][5];
-                if (c == '4')
-                    ipv6enabled = 0;
-                else if (c == '6')
-                    ipv6enabled = 1;
-                else {
-                    printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                    exit(1);
-                }
-            }
-            else {
-                printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                exit(1);
-            }
-
-            if (argvoffset != argi - 1) {
-                printf("Argument must come first: %s.\n", argv[argi]);
-                exit(1);
-            }
-
-            argvoffset++;
-        }
+    int argvoffset = cmdline_parsefor_ipv46(argc, argv, &ipv6enabled);
+    if (argvoffset < 0)
+        exit(1);
 
     if (argc < argvoffset + 2) {
         printf("Usage: %s [--ipv4|--ipv6] filename\n", argv[0]);
diff --git a/testing/Messenger_test.c b/testing/Messenger_test.c
index e7a75c8c..14d9ca20 100644
--- a/testing/Messenger_test.c
+++ b/testing/Messenger_test.c
@@ -97,33 +97,9 @@ int main(int argc, char *argv[])
 {
     /* let user override default by cmdline */
     uint8_t ipv6enabled = TOX_ENABLE_IPV6_DEFAULT; /* x */
-
-    int argvoffset = 0, argi;
-    for(argi = 1; argi < argc; argi++)
-        if (!strncasecmp(argv[argi], "--ipv", 5)) {
-            if (argv[argi][5] && !argv[argi][6]) {
-                char c = argv[argi][5];
-                if (c == '4')
-                    ipv6enabled = 0;
-                else if (c == '6')
-                    ipv6enabled = 1;
-                else {
-                    printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                    exit(1);
-                }
-            }
-            else {
-                printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                exit(1);
-            }
-
-            if (argvoffset != argi - 1) {
-                printf("Argument must come first: %s.\n", argv[argi]);
-                exit(1);
-            }
-
-            argvoffset++;
-        }
+    int argvoffset = cmdline_parsefor_ipv46(argc, argv, &ipv6enabled);
+    if (argvoffset < 0)
+        exit(1);
 
     /* with optional --ipvx, now it can be 1-4 arguments... */
     if ((argc != argvoffset + 2) && (argc != argvoffset + 4)) {
diff --git a/testing/nTox.c b/testing/nTox.c
index 6eeec5d3..750970f9 100644
--- a/testing/nTox.c
+++ b/testing/nTox.c
@@ -544,33 +544,9 @@ int main(int argc, char *argv[])
 
     /* let user override default by cmdline */
     uint8_t ipv6enabled = TOX_ENABLE_IPV6_DEFAULT; /* x */
-
-    int argvoffset = 0, argi;
-    for(argi = 1; argi < argc; argi++)
-        if (!strncasecmp(argv[argi], "--ipv", 5)) {
-            if (argv[argi][5] && !argv[argi][6]) {
-                char c = argv[argi][5];
-                if (c == '4')
-                    ipv6enabled = 0;
-                else if (c == '6')
-                    ipv6enabled = 1;
-                else {
-                    printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                    exit(1);
-                }
-            }
-            else {
-                printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
-                exit(1);
-            }
-
-            if (argvoffset != argi - 1) {
-                printf("Argument must come first: %s.\n", argv[argi]);
-                exit(1);
-            }
-
-            argvoffset++;
-        }
+    int argvoffset = cmdline_parsefor_ipv46(argc, argv, &ipv6enabled);
+    if (argvoffset < 0)
+        exit(1);
 
     int on = 0;
     int c = 0;
diff --git a/toxcore/util.c b/toxcore/util.c
index 19d464d4..7b5ddc49 100644
--- a/toxcore/util.c
+++ b/toxcore/util.c
@@ -43,6 +43,38 @@ void id_cpy(uint8_t *dest, uint8_t *src)
     memcpy(dest, src, CLIENT_ID_SIZE);
 }
 
+int cmdline_parsefor_ipv46(int argc, char **argv, uint8_t *ipv6enabled)
+{
+    int argvoffset = 0, argi;
+    for(argi = 1; argi < argc; argi++)
+        if (!strncasecmp(argv[argi], "--ipv", 5)) {
+            if (argv[argi][5] && !argv[argi][6]) {
+                char c = argv[argi][5];
+                if (c == '4')
+                    *ipv6enabled = 0;
+                else if (c == '6')
+                    *ipv6enabled = 1;
+                else {
+                    printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
+                    return -1;
+                }
+            }
+            else {
+                printf("Invalid argument: %s. Try --ipv4 or --ipv6!\n", argv[argi]);
+                return -1;
+            }
+
+            if (argvoffset != argi - 1) {
+                printf("Argument must come first: %s.\n", argv[argi]);
+                return -1;
+            }
+
+            argvoffset++;
+        }
+
+    return argvoffset;
+};
+
 #ifdef LOGGING
 char logbuffer[512];
 static FILE *logfile = NULL;
diff --git a/toxcore/util.h b/toxcore/util.h
index 71be84ca..e7be2d51 100644
--- a/toxcore/util.h
+++ b/toxcore/util.h
@@ -16,6 +16,8 @@ uint64_t random_64b();
 bool id_eq(uint8_t *dest, uint8_t *src);
 void id_cpy(uint8_t *dest, uint8_t *src);
 
+int cmdline_parsefor_ipv46(int argc, char **argv, uint8_t *ipv6enabled);
+
 #undef LOGGING
 /* #define LOGGING */
 #ifdef LOGGING