[Freeswitch-users] Clustering FreeSWITCH

Thomas Mangin thomas.mangin at exa-networks.co.uk
Thu Oct 30 12:37:07 PDT 2008


Sorry for jumping in without reading the whole thread correctly but I  
will most likely not have the time to do so before Saturday but would  
still provide some feedback.

When using Openser as a customer phone proxy, it is my understanding  
that unless you use the PATH extension you will have problem with  
firewalls as the packet from Freeswitch will not match the opened IP  
address for the UDP port.
In the scenario where the phone send a REGISTER this way : Phone ->  
Firewall (create an association) -> OpenSer -> Freeswitch.
If Freeswitch answers directly to the packet, it will not match the  
association on the firewall for the return packet (different IP) and  
the connection may/will be blocked, so the reply to the REGISTER must  
come back via OpenSER.
Same thing for the INVITE message, if FS tries to connect the firewall  
directly the packet will be blocked.
As well, the firewall mapping need to be kept open with some kind of  
SIP pinging using OPTIONS - for example - and going through OpenSER as  
well from the FS server

When quickly looking into it a few weeks ago - before I was side  
tracked, I found that the way OpenSER and FS way of using SIP PATH are  
not working together very well (I was planning a mail to the list with  
more info once I checked this more extensively).

I can see the point with trying to not use OpenSER and use DNS SRV but  
you may not always be able to do without.



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