Here is what you need to do.
Firstly, get the container id by using command
docker ps
After that use the below command which will give you the container IP.
docker inspect container_id
Go to the Network setting in the bottom where you can find your container's IP.
Or
You can first find the server Ip using command
ifconfig
And then to find the IP of a container use below commands.
docker inspect container_id | grep server_ip