ESP32 AP Mode Local IP

[Fideus]

Board

ESP32

Device Description

Custom Board

Hardware Configuration

not relevant

Version

v1.0.6

IDE Name

Arduino

Operating System

Windows 10

Flash frequency

80

PSRAM enabled

no

Upload speed

921600

Description

Hello all,

I got a Problem Setting up an Access Point. there seems to be an DHCP server starting at Address x.x.x.241. This will cause an Problem if setting up the local IP in this range, like the example below.
Is there a option that this would be possible?
For my actual project the local IP Address could be changed by an user, and so this could cause problems.
Actual it works if I limit the local IP to x.x.x.240 But it would me more flexible if this isn't necessarry

Sketch

#include <WiFi.h>

IPAddress local_IP(192,168,1,254);
IPAddress gateway(192,168,1,9);
IPAddress subnet(255,255,255,0);

void setup()
{
  Serial.begin(115200);
  Serial.println();

  Serial.print("Setting soft-AP configuration ... ");
  Serial.println(WiFi.softAPConfig(local_IP, gateway, subnet) ? "Ready" : "Failed!");

  Serial.print("Setting soft-AP ... ");
  Serial.println(WiFi.softAP("ESPsoftAP_01") ? "Ready" : "Failed!");

  Serial.print("Soft-AP IP address = ");
  Serial.println(WiFi.softAPIP());
}

void loop() {}

Debug Message

Setting soft-AP configuration ... Failed!
Setting soft-AP ... Ready
Soft-AP IP address = 192.168.1.254

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[SuGlider]

@Fideus

Regarding your specific question about using an IP address within DHCP Server range, you may want to set DHCP server parameters to add x.x.x.254 as a Reserved IP Address. It may be possible depending on your router options or on your Linux DHCP Server (I don't have any information about your network or DHCP server).

Or you may want to set ESP Static IP out of DHCP range, but still in the range within the same netmask.

Anyway, this is not related to ESP32 setup or ESP Arduino.

Observation:

The return (false) from softAPConfig(), although still sets the Static IP, is being fixed for the release of Arduino Core 2.0.3.
I see that you reported this issue for the Core 1.0.6.

If you want, you can try to apply the PR #6294 to your local machine with 1.0.6.

[Fideus]

Hello SuGlider,

Thank you for your help.

It isn't only the false return what is the problem. I also can't connect to the ESP32 with my device.
My device which trying to connect to the esp can't resolve an IP address.
Regarding your PR #6294 it seems that the DHCP server is stopped when the Local_Ip is within the DHCP Range.

Is there a way to exclude the Local_Ip from the DHCP server which is running on the ESP32? Or reconfiguring the DHCP range?

With the AccesPoint mode on the ESP there is no external router

[SuGlider]

@Fideus

Is there a way to exclude the Local_Ip from the DHCP server which is running on the ESP32? Or reconfiguring the DHCP range?

Looking the code: https://github.com/espressif/arduino-esp32/blob/master/libraries/WiFi/src/WiFiGeneric.cpp#L139-L148
It is clear that when a Static IP address is assigned to ESP32 in AP mode, it will set a DHCP range from IPaddr + 1 to IPaddr + 11.

Because your example assigns x.x.x.254, it is already at the end of network addressing space and it fails with DHCPS Set Lease Failed! 0x5001 message (in order to see it, turn "Core Debug Level:" to "Verbose").

As you already said, assigning static IP as 192.168.1.240 (instead of .254) works fine.

---

I will work a fix for this issue anyway.

[SuGlider]

@Fideus
PR #6296 will make your example to work.
Using 192.168.1.254 as IP Address for the AP Server will move DHCP range to 192.168.1.1 -- 192.168.1.11

I think this covers your request and solves this issue.
Please let me know.