Version

We found the best version to be 1.0.1.12. The version 1.0.1.9 which we found on Grandstream’s web site has the bug that it does not increase the sequence number of the Re-INVITE to put someone off-hold, making the PBX discard that message, so that the other person stay on hold for ever.

NAT

The GXP-2000 supports various ways to allocate a public IP address. However, as the pbxnsip PBX has a session border controller built-in, people should refrain from using this GXP feature. Usually it only causes additional trouble (symmetrical NAT, wanne-be smart firewalls).