Hello world 
I had connectivity issues with my BambuLab X1C from Linux application running on FreeBSD. After troubleshooting was caused by firewall blocking printer broadcasts from port 1990/2021. This can be fixed by adding firewall rule that accepts packets from printer IP src-port 1990,2021 to ANY address (not only to “me”). After adding this rule all works fine, connection is initiated by the host so stateful firewall will accept following connections, it is possible to upload models, view camera, etc.
I have asked BambuLab to provide table with all network ports and protocols involved, and here it is:
https://wiki.bambulab.com/en/general/printer-network-ports
I hope this helps anyone who faces similar issues