Voice chat to to msn users through spark on openfire 3.7.0

hi guys i am using openfire 3.7.0 on a linux (CentOS) server and spark 2.5.8 on vista and xp workstations as client.

Everything goes well but i canot make pc to pc calls. i am running behind a manually built firewall. which protocol and port(s) do i have to enable but this call functionality will work.

Remember anytime i try to make this call, i get this error message: ‘’ voice chat ended.no media received. this may be caused by a firewall configuration problem.
justmarried.jar (222655 Bytes)