It is allowed to set server domain name as external address in flashphoner.properties file, for example
ip=test.flashphoner.com
Also dynamic DNS domains may be used, for example
ip=wcs.dyndns.com
Anyway, the name should match current external IP address of the server.
While IP address or another DNS record parameters are changing, publishing and playback failures are posssible until DNS record update is deployed to all DNS servers.