I am installing Linksys PAP2 (ATA : analog telephone adapter) in my network protected bby ISA Server 2006. The PAP2 open first 5060 port (SIP protocol) and for each call RTP protocal is used. I open all outband traffic in ISA server for my PAP2. When connecting the PAP2, 5060 port is open (Action : initiated connection - Result Code : 0x0 ERROR_SUCCESS). If there is no activity on the PAP, after excatly 60 sec the connection is closed (Action : Closed connection - Result code : 0x80074e20 FWX_E_GRACEFUL_SHUTDOWN) When the connection is closed, the PAP stop working. Please can some when help me thanching the ISA server configuration to let le 5060 port open. Thanx
SIP is a complex protocol and it implemented in a variety of ways. That's why some products work and some don't and some don't even use SIP, such as Lingo, and so there's no problem putting them behind NAT devices.