The problem at hand is that with Docker, containers have different IP addresses on start. Even after a successful data migration or simply a restart of your container, you need to propagate that new information. For example let your app container know that the database changed IP address.

Ip over dns for public wifi
tuto: http://vincesafe.fr/2012/08/26/contournez-restrictions-et-censure-avec-lip-over-dns/

Consider two people on the same open WLAN: Bob and Eve. Eve wants to get Bob to visit a malicious webpage she created so that she can install malware onto Bob’s computer via a drive-by download, or perhaps show a spoofed website to try and steal Bob’s credentials.