Content Server, wireless inaccessible on local network, but work locally (Mac)

[basker]

Hi,

On macOS Big Sur, I'm having trouble with the content server and wireless client connection. They used to work, but seem to no longer work. Maybe with the 5.20/5.21 update. The settings are the defaults.

I can see the calibre process listening on 0.0.0.0 for ports 8080 and 9090 with netstat and GUI programs. In the Calibre interface it says it's sharing on the actual DHCP supplied IPs.

On the mac where Calibre is running I can access the content server on all the local IP addresses -- 127.0.0.1 and the addresses provided by DHCP to the ethernet and wireless connections. No problem here.

For other computers on the same network, I cannot reach the content server. My firewall settings are set to allow Calibre. However if I disable the firewall I still have the problem.

What really confuses me is that if I quit calibre and run a different web server on ports port 8080 and 9090, then I can see the server and view files with the firewall on or disabled. No blocking.

For example, if I run `python3 -m http.server 8080`, I have no problems getting to the caliber mac from any other machine on my network.

I also noticed that if I run a network scanner against my mac, then when Calibre is not running ports 8080 and 9090 show as closed. When I run Calibre, the ports show as "blocked".

The other ports where apps are running show as open and respond to the scan. Calibre is the only app that's not able to respond to network requests.

I've tried all the normal troubleshooting, including deleting my system and firewall prefs so they have the default settings.

Has anyone else seen this sort of thing?

Thanks,

B