Today all four proxies are supplying the correct "Connection Information" IP address (RTP address). Below are results from my tests done on 2009-06-02 and 2009-06-08 (today).
Code:
2009-06-02 2009-06-08
SERVER RTP address RTP address
proxy01.us1.voxalot.com 64.34.163.35 64.34.163.35
proxy02.us1.voxalot.com my_public_ip 64.34.173.199
proxy01.eu1.voxalot.com 85.17.19.194 85.17.19.194
proxy01.au1.voxalot.com 202.60.88.238 202.60.88.238
I don't have a symmetric NAT router available for testing, but I suspect that a user receiving a call behind a symmetric NAT router will not hear audio if his SIP device is configured with the usual NAT settings. This is because the SIP device configured with NAT settings will learn its public IP address during the registration process and will use its public IP address in the "Contact" line. The Voxalot proxy, on seeing the correct public IP address in the "Contact" line, will disable its RTP proxy function for that call and give the callee's public IP address to the caller in "Connection Information". If this is in fact what happens, users behind symmetric NAT can avoid the problem by configuring their devices as if for use on a public IP address. Specifically, set "NAT Mapping Enable:" = no. Because this is counter-intuitive many users may need to be told how to handle symmetric NAT.