Is captive portal supposed to work with iPhone?

[yanshay]

I got edge-dhcp working as dhcp server on esp32s3 (esp-hal).

I saw there is configuration there for captive portal. My understanding this is so when the client (e.g. phone) connects to the AP it launches a web page, like in airports wifi, is that correct?

I configured this (all I had to do is set server_options.captive_url=Some("http://...") and connected with an iPhone the phone didn't go to the page automatically. Everything else is working, so I can go to the web page of the web server on the esp32s3.

Should it be working the way I expec it to?

I saw in #31 it's said to work but mentions some Option 14 which I don't know what it is.

I'm using:

edge-nal-embassy = "0.4.1"
edge-dhcp = "0.4.0"
edge-nal = "0.4.2"

[ivmarkov]

What "page"?
What the edge-captive project does is just one aspect of the notion of a "Captive Portal". Namely, a local DNS "captive" server that answers all domain requests with a fixed IP. I.e. everything the user types in the browser.

To implement a Captive Portal, you also need to (a) implement a small HTTP server - maybe with edge-http - that will display a web page to the user, asking for her wireless credentials.

Then (b) you also need to configure the DHCP server to provide as a DNS the IP where the captive DNS listens (the gateway IP of the esp).

All of the above is possible and works, yes, but is some effort.

UPDATE: P.S. For IP subnet, use something non-standard with an external IP range. like 200.200.200.0/24 or something. Not a regular internal network.

[yanshay]

I have the esp32 in AP running picoserve with a web page http://192.168.2.1/config.
This is what I placed in the captive_url.

Then (b) you also need to configure the DHCP server to provide as a DNS the IP where the captive DNS listens (the gateway IP of the esp).

I didn't use a DNS since the page is IP, is it required?

UPDATE: P.S. For IP subnet, use something non-standard with an external IP range. like 200.200.200.0/24 or something. Not a regular internal network.

So the IP range I used won't work (internal)?

[ivmarkov]

I have the esp32 in AP running picoserve with a web page http://192.168.2.1/config. This is what I placed in the captive_url.

I have actually not seen this captive_url thing used in the field. All device I've probed do not (yet?) rely on this option to detect a captive portal and do the old fashioned probing with fixed URLs trick that you can google on the internet.

For their probing to be successful or at least fast in detecting the captive portal, you do need the captive-portal project and you do need to run its captive dns. This way their probes will not timeout but will return 404 as they will be redirected to your web server.

Also, if the dhcp option you are using is not used by the android device, it has no way to figure out the captive portal URL other than relying on your http server and the captive DNS.

I didn't use a DNS since the page is IP, is it required?

See above.

So the IP range I used won't work (internal)?

Nope.

[yanshay]

I googled about probing, my understanding that as my iPhone joins a wifi network, it tries to access http://captive.apple.com. If something is there it will show up.

So the captive-portal poject is basically a DNS that responds to any request with the IP given to it, and then my web server, which is listening on that ip, will be able to respond to redirect, is that correct?

So I setup the captive-portal and implemented on my web server a custome handler that will log any request that I don't handle (and I verified it's working), but nothing happens.
I expected to see some request coming in once I joined with my phone the device AP wifi, but nothing showed up.

Did I understand how it should work correctly?
If so, is something wrong with my code?

This is how I did it based on the example on the crate.
I'm using 0.4.0

#[embassy_executor::task]
async fn captive(stack: Stack<'static>) {
    let udp_buffers: edge_nal_embassy::UdpBuffers<5, 1024, 1024, 5> = edge_nal_embassy::UdpBuffers::new();
    let udp = edge_nal_embassy::Udp::new(stack, &udp_buffers);

    let mut tx_buf = [0; 1500];
    let mut rx_buf = [0; 1500];
    edge_captive::io::run(
        &udp,
        SocketAddr::new(IpAddr::V4(Ipv4Addr::UNSPECIFIED), 53),
        &mut tx_buf,
        &mut rx_buf,
        Ipv4Addr::new(192, 168, 2, 1),
        core::time::Duration::from_secs(60),
    ).await.unwrap();
}

[ivmarkov]

I googled about probing, my understanding that as my iPhone joins a wifi network, it tries to access http://captive.apple.com. If something is there it will show up.

I do not understand "it will show up". What will show up where?
The whole idea of the probing is that if there is a captive DNS between your phone and captive.apple.com, then the phone will NOT get the output captive.apple.com returns, but something else. That's how the phone figures out it is behind a captive dns: "hey I did NOT get from captive.apple.com what I expected, so there MUST be a proxy/captive portal in between".

So the captive-portal poject is basically a DNS that responds to any request with the IP given to it, and then my web server, which is listening on that ip, will be able to respond to redirect, is that correct?

Yes, if by "respond to redirect" you mean "respond WITH a redirect".

So I setup the captive-portal and implemented on my web server a custome handler that will log any request that I don't handle (and I verified it's working), but nothing happens. I expected to see some request coming in once I joined with my phone the device AP wifi, but nothing showed up.

Did I understand how it should work correctly? If so, is something wrong with my code?

This is how I did it based on the example on the crate. I'm using 0.4.0

#[embassy_executor::task]
async fn captive(stack: Stack<'static>) {
    let udp_buffers: edge_nal_embassy::UdpBuffers<5, 1024, 1024, 5> = edge_nal_embassy::UdpBuffers::new();
    let udp = edge_nal_embassy::Udp::new(stack, &udp_buffers);

    let mut tx_buf = [0; 1500];
    let mut rx_buf = [0; 1500];
    edge_captive::io::run(
        &udp,
        SocketAddr::new(IpAddr::V4(Ipv4Addr::UNSPECIFIED), 53),
        &mut tx_buf,
        &mut rx_buf,
        Ipv4Addr::new(192, 168, 2, 1),
        core::time::Duration::from_secs(60),
    ).await.unwrap();
}

Do you report 192.168.2.1 as THE DNS server that is to be returned by the DHCP server to its clients?
If you don't it won't work.

If you do, all http://foo.com requests you type in your web browser (ATTENTION: use http:// not https://) should work and you should see these coming to your web server. And the best test is to first try from a web browser.

Other than that, you are still using 192.168.0.X even though we agreed you should use an external IP range for the DHCP network. As in 200.200.200.0

[yanshay]

I managed to get it to work. The issue was that I forgot to set the DNS in the DHCP.

In my case it seems to work well with 192.168.2.1 . I think it didn't work as good with 200.200.200.1 but I tried various configs so might be some mistake.

Maybe it is working in my case because I'm not really trying to connect to the internet, I just want it to be a simple way to get to an application configuration screen. Join the WIFI and a configuration page shows on the phone.

The only minor issue I have now, is that the first time the iPhone joins the wifi the screen shows. If I "cancel" and tell the iphone to continue w/o internet then the screen will not show next time I join the wifi. If I tell it to switch to another network then it will work.

If I force it to 'forget this network' it works once again.

So looks like iPhone behavior I won't be able to workaround.
Still a nice experience for configuring wifi settings configuration for an application.

Thanks for the great libraries.