diff --git a/mongoose.c b/mongoose.c
index 49492fb1..e8e9c758 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -3563,6 +3563,270 @@ struct mg_connection *mg_mqtt_listen(struct mg_mgr *mgr, const char *url,
   return c;
 }
 
+#ifdef MG_ENABLE_LINES
+#line 1 "src/net.c"
+#endif
+
+
+
+
+
+
+
+
+size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list *ap) {
+  size_t old = c->send.len;
+  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
+  return c->send.len - old;
+}
+
+size_t mg_printf(struct mg_connection *c, const char *fmt, ...) {
+  size_t len = 0;
+  va_list ap;
+  va_start(ap, fmt);
+  len = mg_vprintf(c, fmt, &ap);
+  va_end(ap);
+  return len;
+}
+
+static bool mg_atonl(struct mg_str str, struct mg_addr *addr) {
+  uint32_t localhost = mg_htonl(0x7f000001);
+  if (mg_vcasecmp(&str, "localhost") != 0) return false;
+  memcpy(addr->ip, &localhost, sizeof(uint32_t));
+  addr->is_ip6 = false;
+  return true;
+}
+
+static bool mg_atone(struct mg_str str, struct mg_addr *addr) {
+  if (str.len > 0) return false;
+  memset(addr->ip, 0, sizeof(addr->ip));
+  addr->is_ip6 = false;
+  return true;
+}
+
+static bool mg_aton4(struct mg_str str, struct mg_addr *addr) {
+  uint8_t data[4] = {0, 0, 0, 0};
+  size_t i, num_dots = 0;
+  for (i = 0; i < str.len; i++) {
+    if (str.ptr[i] >= '0' && str.ptr[i] <= '9') {
+      int octet = data[num_dots] * 10 + (str.ptr[i] - '0');
+      if (octet > 255) return false;
+      data[num_dots] = (uint8_t) octet;
+    } else if (str.ptr[i] == '.') {
+      if (num_dots >= 3 || i == 0 || str.ptr[i - 1] == '.') return false;
+      num_dots++;
+    } else {
+      return false;
+    }
+  }
+  if (num_dots != 3 || str.ptr[i - 1] == '.') return false;
+  memcpy(&addr->ip, data, sizeof(data));
+  addr->is_ip6 = false;
+  return true;
+}
+
+static bool mg_v4mapped(struct mg_str str, struct mg_addr *addr) {
+  int i;
+  uint32_t ipv4;
+  if (str.len < 14) return false;
+  if (str.ptr[0] != ':' || str.ptr[1] != ':' || str.ptr[6] != ':') return false;
+  for (i = 2; i < 6; i++) {
+    if (str.ptr[i] != 'f' && str.ptr[i] != 'F') return false;
+  }
+  // struct mg_str s = mg_str_n(&str.ptr[7], str.len - 7);
+  if (!mg_aton4(mg_str_n(&str.ptr[7], str.len - 7), addr)) return false;
+  memcpy(&ipv4, addr->ip, sizeof(ipv4));
+  memset(addr->ip, 0, sizeof(addr->ip));
+  addr->ip[10] = addr->ip[11] = 255;
+  memcpy(&addr->ip[12], &ipv4, 4);
+  addr->is_ip6 = true;
+  return true;
+}
+
+static bool mg_aton6(struct mg_str str, struct mg_addr *addr) {
+  size_t i, j = 0, n = 0, dc = 42;
+  if (str.len > 2 && str.ptr[0] == '[') str.ptr++, str.len -= 2;
+  if (mg_v4mapped(str, addr)) return true;
+  for (i = 0; i < str.len; i++) {
+    if ((str.ptr[i] >= '0' && str.ptr[i] <= '9') ||
+        (str.ptr[i] >= 'a' && str.ptr[i] <= 'f') ||
+        (str.ptr[i] >= 'A' && str.ptr[i] <= 'F')) {
+      unsigned long val;
+      if (i > j + 3) return false;
+      // MG_DEBUG(("%zu %zu [%.*s]", i, j, (int) (i - j + 1), &str.ptr[j]));
+      val = mg_unhexn(&str.ptr[j], i - j + 1);
+      addr->ip[n] = (uint8_t) ((val >> 8) & 255);
+      addr->ip[n + 1] = (uint8_t) (val & 255);
+    } else if (str.ptr[i] == ':') {
+      j = i + 1;
+      if (i > 0 && str.ptr[i - 1] == ':') {
+        dc = n;  // Double colon
+        if (i > 1 && str.ptr[i - 2] == ':') return false;
+      } else if (i > 0) {
+        n += 2;
+      }
+      if (n > 14) return false;
+      addr->ip[n] = addr->ip[n + 1] = 0;  // For trailing ::
+    } else {
+      return false;
+    }
+  }
+  if (n < 14 && dc == 42) return false;
+  if (n < 14) {
+    memmove(&addr->ip[dc + (14 - n)], &addr->ip[dc], n - dc + 2);
+    memset(&addr->ip[dc], 0, 14 - n);
+  }
+
+  addr->is_ip6 = true;
+  return true;
+}
+
+bool mg_aton(struct mg_str str, struct mg_addr *addr) {
+  // MG_INFO(("[%.*s]", (int) str.len, str.ptr));
+  return mg_atone(str, addr) || mg_atonl(str, addr) || mg_aton4(str, addr) ||
+         mg_aton6(str, addr);
+}
+
+struct mg_connection *mg_alloc_conn(struct mg_mgr *mgr) {
+  struct mg_connection *c =
+      (struct mg_connection *) calloc(1, sizeof(*c) + mgr->extraconnsize);
+  if (c != NULL) {
+    c->mgr = mgr;
+    c->send.align = c->recv.align = MG_IO_SIZE;
+    c->id = ++mgr->nextid;
+  }
+  return c;
+}
+
+void mg_close_conn(struct mg_connection *c) {
+  mg_resolve_cancel(c);  // Close any pending DNS query
+  LIST_DELETE(struct mg_connection, &c->mgr->conns, c);
+  if (c == c->mgr->dns4.c) c->mgr->dns4.c = NULL;
+  if (c == c->mgr->dns6.c) c->mgr->dns6.c = NULL;
+  // Order of operations is important. `MG_EV_CLOSE` event must be fired
+  // before we deallocate received data, see #1331
+  mg_call(c, MG_EV_CLOSE, NULL);
+  MG_DEBUG(("%lu %p closed", c->id, c->fd));
+
+  mg_tls_free(c);
+  mg_iobuf_free(&c->recv);
+  mg_iobuf_free(&c->send);
+  memset(c, 0, sizeof(*c));
+  free(c);
+}
+
+struct mg_connection *mg_connect(struct mg_mgr *mgr, const char *url,
+                                 mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = NULL;
+  if (url == NULL || url[0] == '\0') {
+    MG_ERROR(("null url"));
+  } else if ((c = mg_alloc_conn(mgr)) == NULL) {
+    MG_ERROR(("OOM"));
+  } else {
+    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
+    c->is_udp = (strncmp(url, "udp:", 4) == 0);
+    c->fd = (void *) (size_t) MG_INVALID_SOCKET;
+    c->fn = fn;
+    c->is_client = true;
+    c->fn_data = fn_data;
+    MG_DEBUG(("%lu %p %s", c->id, c->fd, url));
+    mg_call(c, MG_EV_OPEN, (void *) url);
+    mg_resolve(c, url);
+    if (mg_url_is_ssl(url)) {
+      struct mg_str host = mg_url_host(url);
+      mg_tls_init(c, host);
+    }
+  }
+  return c;
+}
+
+struct mg_connection *mg_listen(struct mg_mgr *mgr, const char *url,
+                                mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = NULL;
+  if ((c = mg_alloc_conn(mgr)) == NULL) {
+    MG_ERROR(("OOM %s", url));
+  } else if (!mg_open_listener(c, url)) {
+    MG_ERROR(("Failed: %s, errno %d", url, errno));
+    free(c);
+    c = NULL;
+  } else {
+    c->is_listening = 1;
+    c->is_udp = strncmp(url, "udp:", 4) == 0;
+    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
+    c->fn = fn;
+    c->fn_data = fn_data;
+    mg_call(c, MG_EV_OPEN, NULL);
+    if (mg_url_is_ssl(url)) c->is_tls = 1;  // Accepted connection must
+    MG_DEBUG(("%lu %p %s", c->id, c->fd, url));
+  }
+  return c;
+}
+
+struct mg_connection *mg_wrapfd(struct mg_mgr *mgr, int fd,
+                                mg_event_handler_t fn, void *fn_data) {
+  struct mg_connection *c = mg_alloc_conn(mgr);
+  if (c != NULL) {
+    c->fd = (void *) (size_t) fd;
+    c->fn = fn;
+    c->fn_data = fn_data;
+    MG_EPOLL_ADD(c);
+    mg_call(c, MG_EV_OPEN, NULL);
+    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
+  }
+  return c;
+}
+
+struct mg_timer *mg_timer_add(struct mg_mgr *mgr, uint64_t milliseconds,
+                              unsigned flags, void (*fn)(void *), void *arg) {
+  struct mg_timer *t = (struct mg_timer *) calloc(1, sizeof(*t));
+  if (t != NULL) {
+    mg_timer_init(&mgr->timers, t, milliseconds, flags, fn, arg);
+    t->id = mgr->timerid++;
+  }
+  return t;
+}
+
+void mg_mgr_free(struct mg_mgr *mgr) {
+  struct mg_connection *c;
+  struct mg_timer *tmp, *t = mgr->timers;
+  while (t != NULL) tmp = t->next, free(t), t = tmp;
+  mgr->timers = NULL;  // Important. Next call to poll won't touch timers
+  for (c = mgr->conns; c != NULL; c = c->next) c->is_closing = 1;
+  mg_mgr_poll(mgr, 0);
+#if MG_ENABLE_FREERTOS_TCP
+  FreeRTOS_DeleteSocketSet(mgr->ss);
+#endif
+  MG_DEBUG(("All connections closed"));
+#if MG_ENABLE_EPOLL
+  if (mgr->epoll_fd >= 0) close(mgr->epoll_fd), mgr->epoll_fd = -1;
+#endif
+  mg_tls_ctx_free(mgr);
+}
+
+void mg_mgr_init(struct mg_mgr *mgr) {
+  memset(mgr, 0, sizeof(*mgr));
+#if MG_ENABLE_EPOLL
+  if ((mgr->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
+    MG_ERROR(("epoll_create1 errno %d", errno));
+#else
+  mgr->epoll_fd = -1;
+#endif
+#if MG_ARCH == MG_ARCH_WIN32 && MG_ENABLE_WINSOCK
+  // clang-format off
+  { WSADATA data; WSAStartup(MAKEWORD(2, 2), &data); }
+  // clang-format on
+#elif MG_ENABLE_FREERTOS_TCP
+  mgr->ss = FreeRTOS_CreateSocketSet();
+#elif defined(__unix) || defined(__unix__) || defined(__APPLE__)
+  // Ignore SIGPIPE signal, so if client cancels the request, it
+  // won't kill the whole process.
+  signal(SIGPIPE, SIG_IGN);
+#endif
+  mgr->dnstimeout = 3000;
+  mgr->dns4.url = "udp://8.8.8.8:53";
+  mgr->dns6.url = "udp://[2001:4860:4860::8888]:53";
+}
+
 #ifdef MG_ENABLE_LINES
 #line 1 "src/net_builtin.c"
 #endif
@@ -4116,21 +4380,43 @@ static struct mg_connection *accept_conn(struct mg_connection *lsn,
   return c;
 }
 
+static size_t trim_len(struct mg_connection *c, size_t len) {
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
+  size_t eth_h_len = 14, ip_max_h_len = 24, tcp_max_h_len = 60, udp_h_len = 8;
+  size_t max_headers_len = eth_h_len + ip_max_h_len +
+                          (c->is_udp ? udp_h_len : tcp_max_h_len);
+  size_t min_mtu = c->is_udp ? 68 /* RFC-791 */ : max_headers_len - eth_h_len;
+
+  // If the frame exceeds the available buffer, trim the length
+  if (len + max_headers_len > ifp->tx.len) {
+    len = ifp->tx.len - max_headers_len;
+  }
+  // Ensure the MTU isn't lower than the minimum allowed value
+  if (ifp->mtu < min_mtu) {
+    MG_ERROR(("MTU is lower than minimum possible value. Setting it to %d.",
+              min_mtu));
+    ifp->mtu = (uint16_t) min_mtu;
+  }
+  // If the total packet size exceeds the MTU, trim the length
+  if (len + max_headers_len - eth_h_len > ifp->mtu) {
+    len = ifp->mtu - max_headers_len + eth_h_len;
+    if (c->is_udp) {
+      MG_ERROR(("UDP datagram exceeds MTU. Truncating it."));
+    }
+  }
+
+  return len;
+}
+
 long mg_io_send(struct mg_connection *c, const void *buf, size_t len) {
   struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
   struct connstate *s = (struct connstate *) (c + 1);
   uint32_t rem_ip;
   memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
+  len = trim_len(c, len);
   if (c->is_udp) {
-    size_t max_headers_len = 14 + 24 /* max IP */ + 8 /* UDP */;
-    if (len + max_headers_len > ifp->tx.len) {
-      len = ifp->tx.len - max_headers_len;
-    }
     tx_udp(ifp, s->mac, ifp->ip, c->loc.port, rem_ip, c->rem.port, buf, len);
   } else {
-    size_t max_headers_len = 14 + 24 /* max IP */ + 60 /* max TCP */;
-    if (len + max_headers_len > ifp->tx.len)
-      len = ifp->tx.len - max_headers_len;
     if (tx_tcp(ifp, s->mac, rem_ip, TH_PUSH | TH_ACK, c->loc.port, c->rem.port,
                mg_htonl(s->seq), mg_htonl(s->ack), buf, len) > 0) {
       s->seq += (uint32_t) len;
@@ -4509,6 +4795,7 @@ void mg_tcpip_init(struct mg_mgr *mgr, struct mg_tcpip_if *ifp) {
     ifp->timer_1000ms = mg_millis();
     mgr->priv = ifp;
     ifp->mgr = mgr;
+    ifp->mtu = MG_TCPIP_MTU_DEFAULT;
     mgr->extraconnsize = sizeof(struct connstate);
     if (ifp->ip == 0) ifp->enable_dhcp_client = true;
     memset(ifp->gwmac, 255, sizeof(ifp->gwmac));  // Set to broadcast
@@ -4649,6 +4936,7 @@ bool mg_send(struct mg_connection *c, const void *buf, size_t len) {
     mg_error(c, "net down");
   } else if (c->is_udp) {
     struct connstate *s = (struct connstate *) (c + 1);
+    len = trim_len(c, len);   // Trimming length if necessary
     tx_udp(ifp, s->mac, ifp->ip, c->loc.port, rem_ip, c->rem.port, buf, len);
     res = true;
   } else {
@@ -4658,270 +4946,6 @@ bool mg_send(struct mg_connection *c, const void *buf, size_t len) {
 }
 #endif  // MG_ENABLE_TCPIP
 
-#ifdef MG_ENABLE_LINES
-#line 1 "src/net.c"
-#endif
-
-
-
-
-
-
-
-
-size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list *ap) {
-  size_t old = c->send.len;
-  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
-  return c->send.len - old;
-}
-
-size_t mg_printf(struct mg_connection *c, const char *fmt, ...) {
-  size_t len = 0;
-  va_list ap;
-  va_start(ap, fmt);
-  len = mg_vprintf(c, fmt, &ap);
-  va_end(ap);
-  return len;
-}
-
-static bool mg_atonl(struct mg_str str, struct mg_addr *addr) {
-  uint32_t localhost = mg_htonl(0x7f000001);
-  if (mg_vcasecmp(&str, "localhost") != 0) return false;
-  memcpy(addr->ip, &localhost, sizeof(uint32_t));
-  addr->is_ip6 = false;
-  return true;
-}
-
-static bool mg_atone(struct mg_str str, struct mg_addr *addr) {
-  if (str.len > 0) return false;
-  memset(addr->ip, 0, sizeof(addr->ip));
-  addr->is_ip6 = false;
-  return true;
-}
-
-static bool mg_aton4(struct mg_str str, struct mg_addr *addr) {
-  uint8_t data[4] = {0, 0, 0, 0};
-  size_t i, num_dots = 0;
-  for (i = 0; i < str.len; i++) {
-    if (str.ptr[i] >= '0' && str.ptr[i] <= '9') {
-      int octet = data[num_dots] * 10 + (str.ptr[i] - '0');
-      if (octet > 255) return false;
-      data[num_dots] = (uint8_t) octet;
-    } else if (str.ptr[i] == '.') {
-      if (num_dots >= 3 || i == 0 || str.ptr[i - 1] == '.') return false;
-      num_dots++;
-    } else {
-      return false;
-    }
-  }
-  if (num_dots != 3 || str.ptr[i - 1] == '.') return false;
-  memcpy(&addr->ip, data, sizeof(data));
-  addr->is_ip6 = false;
-  return true;
-}
-
-static bool mg_v4mapped(struct mg_str str, struct mg_addr *addr) {
-  int i;
-  uint32_t ipv4;
-  if (str.len < 14) return false;
-  if (str.ptr[0] != ':' || str.ptr[1] != ':' || str.ptr[6] != ':') return false;
-  for (i = 2; i < 6; i++) {
-    if (str.ptr[i] != 'f' && str.ptr[i] != 'F') return false;
-  }
-  // struct mg_str s = mg_str_n(&str.ptr[7], str.len - 7);
-  if (!mg_aton4(mg_str_n(&str.ptr[7], str.len - 7), addr)) return false;
-  memcpy(&ipv4, addr->ip, sizeof(ipv4));
-  memset(addr->ip, 0, sizeof(addr->ip));
-  addr->ip[10] = addr->ip[11] = 255;
-  memcpy(&addr->ip[12], &ipv4, 4);
-  addr->is_ip6 = true;
-  return true;
-}
-
-static bool mg_aton6(struct mg_str str, struct mg_addr *addr) {
-  size_t i, j = 0, n = 0, dc = 42;
-  if (str.len > 2 && str.ptr[0] == '[') str.ptr++, str.len -= 2;
-  if (mg_v4mapped(str, addr)) return true;
-  for (i = 0; i < str.len; i++) {
-    if ((str.ptr[i] >= '0' && str.ptr[i] <= '9') ||
-        (str.ptr[i] >= 'a' && str.ptr[i] <= 'f') ||
-        (str.ptr[i] >= 'A' && str.ptr[i] <= 'F')) {
-      unsigned long val;
-      if (i > j + 3) return false;
-      // MG_DEBUG(("%zu %zu [%.*s]", i, j, (int) (i - j + 1), &str.ptr[j]));
-      val = mg_unhexn(&str.ptr[j], i - j + 1);
-      addr->ip[n] = (uint8_t) ((val >> 8) & 255);
-      addr->ip[n + 1] = (uint8_t) (val & 255);
-    } else if (str.ptr[i] == ':') {
-      j = i + 1;
-      if (i > 0 && str.ptr[i - 1] == ':') {
-        dc = n;  // Double colon
-        if (i > 1 && str.ptr[i - 2] == ':') return false;
-      } else if (i > 0) {
-        n += 2;
-      }
-      if (n > 14) return false;
-      addr->ip[n] = addr->ip[n + 1] = 0;  // For trailing ::
-    } else {
-      return false;
-    }
-  }
-  if (n < 14 && dc == 42) return false;
-  if (n < 14) {
-    memmove(&addr->ip[dc + (14 - n)], &addr->ip[dc], n - dc + 2);
-    memset(&addr->ip[dc], 0, 14 - n);
-  }
-
-  addr->is_ip6 = true;
-  return true;
-}
-
-bool mg_aton(struct mg_str str, struct mg_addr *addr) {
-  // MG_INFO(("[%.*s]", (int) str.len, str.ptr));
-  return mg_atone(str, addr) || mg_atonl(str, addr) || mg_aton4(str, addr) ||
-         mg_aton6(str, addr);
-}
-
-struct mg_connection *mg_alloc_conn(struct mg_mgr *mgr) {
-  struct mg_connection *c =
-      (struct mg_connection *) calloc(1, sizeof(*c) + mgr->extraconnsize);
-  if (c != NULL) {
-    c->mgr = mgr;
-    c->send.align = c->recv.align = MG_IO_SIZE;
-    c->id = ++mgr->nextid;
-  }
-  return c;
-}
-
-void mg_close_conn(struct mg_connection *c) {
-  mg_resolve_cancel(c);  // Close any pending DNS query
-  LIST_DELETE(struct mg_connection, &c->mgr->conns, c);
-  if (c == c->mgr->dns4.c) c->mgr->dns4.c = NULL;
-  if (c == c->mgr->dns6.c) c->mgr->dns6.c = NULL;
-  // Order of operations is important. `MG_EV_CLOSE` event must be fired
-  // before we deallocate received data, see #1331
-  mg_call(c, MG_EV_CLOSE, NULL);
-  MG_DEBUG(("%lu %p closed", c->id, c->fd));
-
-  mg_tls_free(c);
-  mg_iobuf_free(&c->recv);
-  mg_iobuf_free(&c->send);
-  memset(c, 0, sizeof(*c));
-  free(c);
-}
-
-struct mg_connection *mg_connect(struct mg_mgr *mgr, const char *url,
-                                 mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = NULL;
-  if (url == NULL || url[0] == '\0') {
-    MG_ERROR(("null url"));
-  } else if ((c = mg_alloc_conn(mgr)) == NULL) {
-    MG_ERROR(("OOM"));
-  } else {
-    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
-    c->is_udp = (strncmp(url, "udp:", 4) == 0);
-    c->fd = (void *) (size_t) MG_INVALID_SOCKET;
-    c->fn = fn;
-    c->is_client = true;
-    c->fn_data = fn_data;
-    MG_DEBUG(("%lu %p %s", c->id, c->fd, url));
-    mg_call(c, MG_EV_OPEN, (void *) url);
-    mg_resolve(c, url);
-    if (mg_url_is_ssl(url)) {
-      struct mg_str host = mg_url_host(url);
-      mg_tls_init(c, host);
-    }
-  }
-  return c;
-}
-
-struct mg_connection *mg_listen(struct mg_mgr *mgr, const char *url,
-                                mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = NULL;
-  if ((c = mg_alloc_conn(mgr)) == NULL) {
-    MG_ERROR(("OOM %s", url));
-  } else if (!mg_open_listener(c, url)) {
-    MG_ERROR(("Failed: %s, errno %d", url, errno));
-    free(c);
-    c = NULL;
-  } else {
-    c->is_listening = 1;
-    c->is_udp = strncmp(url, "udp:", 4) == 0;
-    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
-    c->fn = fn;
-    c->fn_data = fn_data;
-    mg_call(c, MG_EV_OPEN, NULL);
-    if (mg_url_is_ssl(url)) c->is_tls = 1;  // Accepted connection must
-    MG_DEBUG(("%lu %p %s", c->id, c->fd, url));
-  }
-  return c;
-}
-
-struct mg_connection *mg_wrapfd(struct mg_mgr *mgr, int fd,
-                                mg_event_handler_t fn, void *fn_data) {
-  struct mg_connection *c = mg_alloc_conn(mgr);
-  if (c != NULL) {
-    c->fd = (void *) (size_t) fd;
-    c->fn = fn;
-    c->fn_data = fn_data;
-    MG_EPOLL_ADD(c);
-    mg_call(c, MG_EV_OPEN, NULL);
-    LIST_ADD_HEAD(struct mg_connection, &mgr->conns, c);
-  }
-  return c;
-}
-
-struct mg_timer *mg_timer_add(struct mg_mgr *mgr, uint64_t milliseconds,
-                              unsigned flags, void (*fn)(void *), void *arg) {
-  struct mg_timer *t = (struct mg_timer *) calloc(1, sizeof(*t));
-  if (t != NULL) {
-    mg_timer_init(&mgr->timers, t, milliseconds, flags, fn, arg);
-    t->id = mgr->timerid++;
-  }
-  return t;
-}
-
-void mg_mgr_free(struct mg_mgr *mgr) {
-  struct mg_connection *c;
-  struct mg_timer *tmp, *t = mgr->timers;
-  while (t != NULL) tmp = t->next, free(t), t = tmp;
-  mgr->timers = NULL;  // Important. Next call to poll won't touch timers
-  for (c = mgr->conns; c != NULL; c = c->next) c->is_closing = 1;
-  mg_mgr_poll(mgr, 0);
-#if MG_ENABLE_FREERTOS_TCP
-  FreeRTOS_DeleteSocketSet(mgr->ss);
-#endif
-  MG_DEBUG(("All connections closed"));
-#if MG_ENABLE_EPOLL
-  if (mgr->epoll_fd >= 0) close(mgr->epoll_fd), mgr->epoll_fd = -1;
-#endif
-  mg_tls_ctx_free(mgr);
-}
-
-void mg_mgr_init(struct mg_mgr *mgr) {
-  memset(mgr, 0, sizeof(*mgr));
-#if MG_ENABLE_EPOLL
-  if ((mgr->epoll_fd = epoll_create1(EPOLL_CLOEXEC)) < 0)
-    MG_ERROR(("epoll_create1 errno %d", errno));
-#else
-  mgr->epoll_fd = -1;
-#endif
-#if MG_ARCH == MG_ARCH_WIN32 && MG_ENABLE_WINSOCK
-  // clang-format off
-  { WSADATA data; WSAStartup(MAKEWORD(2, 2), &data); }
-  // clang-format on
-#elif MG_ENABLE_FREERTOS_TCP
-  mgr->ss = FreeRTOS_CreateSocketSet();
-#elif defined(__unix) || defined(__unix__) || defined(__APPLE__)
-  // Ignore SIGPIPE signal, so if client cancels the request, it
-  // won't kill the whole process.
-  signal(SIGPIPE, SIG_IGN);
-#endif
-  mgr->dnstimeout = 3000;
-  mgr->dns4.url = "udp://8.8.8.8:53";
-  mgr->dns6.url = "udp://[2001:4860:4860::8888]:53";
-}
-
 #ifdef MG_ENABLE_LINES
 #line 1 "src/ota_dummy.c"
 #endif
diff --git a/mongoose.h b/mongoose.h
index c510a89b..e98d786a 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -1711,6 +1711,8 @@ struct mg_tcpip_if {
   void *driver_data;               // Driver-specific data
   struct mg_mgr *mgr;              // Mongoose event manager
   struct mg_queue recv_queue;      // Receive queue
+  uint16_t mtu;                    // Interface MTU
+#define MG_TCPIP_MTU_DEFAULT 500
 
   // Internal state, user can use it but should not change it
   uint8_t gwmac[6];             // Router's MAC
diff --git a/src/net_builtin.c b/src/net_builtin.c
index f2d5ff75..49eea473 100644
--- a/src/net_builtin.c
+++ b/src/net_builtin.c
@@ -548,21 +548,43 @@ static struct mg_connection *accept_conn(struct mg_connection *lsn,
   return c;
 }
 
+static size_t trim_len(struct mg_connection *c, size_t len) {
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
+  size_t eth_h_len = 14, ip_max_h_len = 24, tcp_max_h_len = 60, udp_h_len = 8;
+  size_t max_headers_len = eth_h_len + ip_max_h_len +
+                          (c->is_udp ? udp_h_len : tcp_max_h_len);
+  size_t min_mtu = c->is_udp ? 68 /* RFC-791 */ : max_headers_len - eth_h_len;
+
+  // If the frame exceeds the available buffer, trim the length
+  if (len + max_headers_len > ifp->tx.len) {
+    len = ifp->tx.len - max_headers_len;
+  }
+  // Ensure the MTU isn't lower than the minimum allowed value
+  if (ifp->mtu < min_mtu) {
+    MG_ERROR(("MTU is lower than minimum possible value. Setting it to %d.",
+              min_mtu));
+    ifp->mtu = (uint16_t) min_mtu;
+  }
+  // If the total packet size exceeds the MTU, trim the length
+  if (len + max_headers_len - eth_h_len > ifp->mtu) {
+    len = ifp->mtu - max_headers_len + eth_h_len;
+    if (c->is_udp) {
+      MG_ERROR(("UDP datagram exceeds MTU. Truncating it."));
+    }
+  }
+
+  return len;
+}
+
 long mg_io_send(struct mg_connection *c, const void *buf, size_t len) {
   struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->mgr->priv;
   struct connstate *s = (struct connstate *) (c + 1);
   uint32_t rem_ip;
   memcpy(&rem_ip, c->rem.ip, sizeof(uint32_t));
+  len = trim_len(c, len);
   if (c->is_udp) {
-    size_t max_headers_len = 14 + 24 /* max IP */ + 8 /* UDP */;
-    if (len + max_headers_len > ifp->tx.len) {
-      len = ifp->tx.len - max_headers_len;
-    }
     tx_udp(ifp, s->mac, ifp->ip, c->loc.port, rem_ip, c->rem.port, buf, len);
   } else {
-    size_t max_headers_len = 14 + 24 /* max IP */ + 60 /* max TCP */;
-    if (len + max_headers_len > ifp->tx.len)
-      len = ifp->tx.len - max_headers_len;
     if (tx_tcp(ifp, s->mac, rem_ip, TH_PUSH | TH_ACK, c->loc.port, c->rem.port,
                mg_htonl(s->seq), mg_htonl(s->ack), buf, len) > 0) {
       s->seq += (uint32_t) len;
@@ -941,6 +963,7 @@ void mg_tcpip_init(struct mg_mgr *mgr, struct mg_tcpip_if *ifp) {
     ifp->timer_1000ms = mg_millis();
     mgr->priv = ifp;
     ifp->mgr = mgr;
+    ifp->mtu = MG_TCPIP_MTU_DEFAULT;
     mgr->extraconnsize = sizeof(struct connstate);
     if (ifp->ip == 0) ifp->enable_dhcp_client = true;
     memset(ifp->gwmac, 255, sizeof(ifp->gwmac));  // Set to broadcast
@@ -1081,6 +1104,7 @@ bool mg_send(struct mg_connection *c, const void *buf, size_t len) {
     mg_error(c, "net down");
   } else if (c->is_udp) {
     struct connstate *s = (struct connstate *) (c + 1);
+    len = trim_len(c, len);   // Trimming length if necessary
     tx_udp(ifp, s->mac, ifp->ip, c->loc.port, rem_ip, c->rem.port, buf, len);
     res = true;
   } else {
diff --git a/src/net_builtin.h b/src/net_builtin.h
index 60f591ab..5cc412df 100644
--- a/src/net_builtin.h
+++ b/src/net_builtin.h
@@ -27,6 +27,8 @@ struct mg_tcpip_if {
   void *driver_data;               // Driver-specific data
   struct mg_mgr *mgr;              // Mongoose event manager
   struct mg_queue recv_queue;      // Receive queue
+  uint16_t mtu;                    // Interface MTU
+#define MG_TCPIP_MTU_DEFAULT 1500
 
   // Internal state, user can use it but should not change it
   uint8_t gwmac[6];             // Router's MAC
diff --git a/test/mip_test.c b/test/mip_test.c
index 4a9f70e8..5e2dcdd9 100644
--- a/test/mip_test.c
+++ b/test/mip_test.c
@@ -8,6 +8,7 @@
 
 static int s_num_tests = 0;
 static bool s_sent_fragment = 0;
+static int s_seg_sent = 0;
 
 #define ASSERT(expr)                                            \
   do {                                                          \
@@ -35,6 +36,10 @@ static void ph(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
 }
 
 static void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
+  (void) c, (void) ev, (void) ev_data, (void) fn_data;
+}
+
+static void frag_recv_fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
   if (ev == MG_EV_ERROR) {
     if (s_sent_fragment) {
       ASSERT(strcmp((char*) ev_data, "Received fragmented packet") == 0);
@@ -43,6 +48,21 @@ static void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
   (void) c, (void) ev_data, (void) fn_data;
 }
 
+static void frag_send_fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
+  static bool s_sent;
+  static int s_seg_sizes[] = {416, 416, 368};
+  if (ev == MG_EV_POLL) {
+    if (!s_sent) {
+      c->send.len = 1200; // setting TCP payload size
+      s_sent = true;
+    }
+  } else if (ev == MG_EV_WRITE) {
+    // Checking TCP segment sizes (ev_data points to the TCP payload length)
+    ASSERT(*(int *) ev_data == s_seg_sizes[s_seg_sent++]);
+  }
+  (void) c, (void) ev_data, (void) fn_data;
+}
+
 static void test_poll(void) {
   int count = 0, i;
   struct mg_mgr mgr;
@@ -217,7 +237,7 @@ static void test_retransmit(void) {
   mg_tcpip_free(&mif);
 }
 
-static void test_fragmentation(void) {
+static void test_frag_recv_path(void) {
   struct mg_mgr mgr;
   struct eth e;
   struct ip ip;
@@ -232,7 +252,7 @@ static void test_fragmentation(void) {
   mif.driver = &driver;
   mif.driver_data = &s_driver_data;
   mg_tcpip_init(&mgr, &mif);
-  mg_http_listen(&mgr, "http://0.0.0.0:0", fn, NULL);
+  mg_http_listen(&mgr, "http://0.0.0.0:0", frag_recv_fn, NULL);
   mgr.conns->pfn = NULL;
   mg_mgr_poll(&mgr, 0);
 
@@ -261,6 +281,34 @@ static void test_fragmentation(void) {
   mg_tcpip_free(&mif);
 }
 
+static void test_frag_send_path(void) {
+  struct mg_mgr mgr;
+  struct mg_tcpip_driver driver;
+  struct mg_tcpip_if mif;
+
+  mg_mgr_init(&mgr);
+  memset(&mif, 0, sizeof(mif));
+  memset(&s_driver_data, 0, sizeof(struct driver_data));
+  driver.init = NULL, driver.tx = if_tx, driver.up = if_up, driver.rx = if_rx;
+  mif.driver = &driver;
+  mif.driver_data = &s_driver_data;
+  mg_tcpip_init(&mgr, &mif);
+  mif.mtu = 500;
+  mg_http_listen(&mgr, "http://0.0.0.0:0", frag_send_fn, NULL);
+  mgr.conns->pfn = NULL;
+  for (int i = 0; i < 10; i++)
+    mg_mgr_poll(&mgr, 0);
+  ASSERT(s_seg_sent == 3);
+  s_driver_data.len = 0;
+  mg_mgr_free(&mgr);
+  mg_tcpip_free(&mif);
+}
+
+static void test_fragmentation(void) {
+  test_frag_recv_path();
+  test_frag_send_path();
+}
+
 int main(void) {
   test_statechange();
   test_poll();