Normally the first thing you would think is that you should use the host network in Docker but this loses the isolation, in that case I'd rather use LXC and a public IP or a full VM with public IP to avoid these issues.
Before you Start
I assume you have also ruled out any firewall issues on either end, that RTP or SIP signaling is not being blocked by either side.
1.) Key Settings in Docker/Ports
Before starting, I assume you have forwarded........
If you are converting a generic wifi IP camera to ethernet, it may not be that simple as many are default hard coded to a static IP of 192.168.1.168 and login info admin/admin.
From there you can login to the camera and assign it to DHCP by going to http://192.168.1.168
For security these cameras +DVR should be on a separate untagged VLAN or if possible a physically isolated non-internet connected switch/network.
The reference below is applicable to many of the r........