Polycom DOC2702A User Manual

Polycom RealPresence Collaboration Server (RMX) 1500/2000/4000 Administrator’s Guide 

Polycom, Inc.

The RMX can be configured to send a FW NAT keep alive message at specific Intervals for the 

RTP, UDP and BFCP channels. 
This is necessary because port mappings in the firewall are kept open only if there is 

network traffic in both directions. The firewall will only allow UDP packets into the 

network through ports that have been used to send packets out. 
By default the RMX sends a FW NAT Keep Alive message every 30 seconds. As there is no 

traffic on the Content and FECC channels as a call begins, the firewall will not allow any 

incoming packets from the Content and FECC channels in until the RMX sends out the first 

of the FW NAT Keep Alive messages 30 seconds after the call starts. 
If Content or FECC are required within the first 30 seconds of a call the FW NAT Keep Alive 

Interval should be modified to a lower value.
To enable and modify FW NAT Keep Alive:
FW NAT Keep Alive is enabled in the New Profile - Advanced dialog box.

>> Select the FW NAT Keep Alive check box and if required, modify the Interval field within 

the range of 5 - 86400 seconds.

In an environment that includes SAM (a Polycom SBC), to ensure that a RealPresence Mobile 

endpoint can send content to a conference the value of the system flag 

NUM_OF_INITIATE_HELLO_MESSAGE_IN_CALL_ESTABLISHMENT must be set to 

at least 3.
For more details on modifying the values of system flags, see "Manually Adding and Deleting