I've added another two network traces: - sip_ice_fs_firefox_flow.png: shows the flow graph between Freeswitch (10.240.0.102) our Message Proxy (137.74.91.166) and Firefox (89.246.67.250) - sip_ice_fs_chrome_flow.png: shows the flow graph between Freeswitch (10.240.0.102) our Message Proxy (137.74.91.166) and Google Chrome (89.246.67.250) As you can see, chrome has a much more aggressive ice behavior than firefox and so the connection is established since Freeswitch sends his ICE Check Message to the write Port at timestamp 4.177... which does not happen, when dealing with Firefox. -- Marko Seidenglanz Softwareentwicklung Telefon: +49 351-21324-261 E-Mail: marko.seidenglanz@modima.de modima GmbH Sitz der Gesellschaft: Altplauen 19, 01187 Dresden Amtsgericht Dresden HRB: 32806 Geschäftsführer: Wolfram Gürlich USt-IdNr: DE232950743