Hi all
Not sure where I'd put arduino related threads on this forum, but because its networking related, this seems the best place.

Im having a odd problem with my NodeMCU's

I recently updated my firewall and my script stopped working, I found that I had accidentally turned off ping between vlans. I allowed ICMP which is usually what ping runs over, but it still appears to be blocked.
So posting on another forum we got to the point where we know its the arduino having issues and not the firewall its self.

Turned on logging on firewall and noticed the following actions:

Ping router from Arduino - See the requests in firewall & arduino gets response. (Red line)
Send external web request from arduino - See requests in firewall & arduino gets response. (Orange Line)
Send web request to internal server - Arduino queries internal DNS and gets IP of web server, but no request send (Nothing in firewall logs) (Yellow and Blue)
Send ping to internal server - Arduino queries same dns server, gets ip, but no request sent (Firewall logs again) (Yellow and Green)

however, sending the ping and web request from desktop, shows both the firewall log blocking the ping request, and the rule allowing the web request.(Brown Purple Pink)

Have attached diagram again to help visualize whats going on
And can attach router logs or rules if required

https://imgur.com/a/g4TipmZ

Also have set a windows PC with the same IP address, and can ping the web server, so I know it's something wrong with the arduino's requests to the web server in particular, and not the firewall?

So for some reason, when doing any network traffic to that particular vlan / subnet from the arduino it wont send the requests.
Other devices with the same IP work fine, and other subnets / vlans work fine, just that particular range?

Things I am going to try tonight after work are
- Try a different IP on that subnet to see if its the IP or the range thats having issues.
- Try a wireshark capture to see if I can see the traffic on the LAN, then see if I can see any issues with the packets.