How to assign a link local address when DHCP client fails:"help wanted"

[amontefusco]

I need to connect ESP8266 device to ISOLATED networks, so networks where there are no services like DHCP and DNS.

While the mDNS and SD-DNS are working very well, I cannot find how to enable the lower layer of zero network configuration, i.e., how to autoconfigure a link-local address in case the DHCP server is not answering.

Could you point me to info on how to activate this feature?

[d-a-v]

That is a fair request.
Currently, DHCP client in both lwIP-v1 and v2 are espressif code that do not use 169.254/16 (link-local).
I think upstream lwIP's DHCP client would do that and we should switch to it.
Before we can do that, you can use a timeout in the standard waiting loop (while (WiFi.status != WL_CONNECTED)...) and call WiFi.config(ip,gateway,subnet,dns) on timeout.

[d-a-v]

Currently, DHCP client in both lwIP-v1 and v2 are espressif code that do not use 169.254/16 (link-local).

I am wrong, lack of sleep. It's DHCP client, and I just enabled AUTOIP in lwip2 #5444

[d-a-v]

closed by #5444