[Serusers] SER server: remote vs local

[xwang@comcast.net]

Hello,

I have two SERs: one on local subnet (192.168.1.x), the other remote. I also
have two exact phones: one with local SER, the other is on the same subnet
with remote SER. Both of them can register correctly to the SER on the same
subnet. However, my local IPphone fails to register to the remote SER. I am
pretty sure the username and password are valid. To verify the username
setup, I have xlite installed on the local network 192.168.1, it can
register to both local and remote server without any problem by the same
account.

I notice that the successful registration always has port information in the
header:
Via: SIP/2.0/UDP
192.168.1.103:5060;rport=5060;branch=z9hG4bK8F05E1B1000941AC83B8205023AD0B8F

The failed registration doesn't:
Via: SIP/2.0/UDP
192.168.1.102;branch=z9hG4bKc0f9cc1144b12ca2;received=24.22.117.57

Can someone shed some light on it?

thanks!
steven