Why doesn the NetMeeting/MSN Messenger/ICQ work through IP Sharing?
Applications that use dynamic session initiations, such as NetMeeting and MSN Messenger, require either special support in the firmware of the NAT device or the use of UPnP and a UPnP aware NAT device. Dynamic Session Initiations Dynamic session initiations are conversations, often carried out over a dedicated protocol (such as Session Initiation Protocol or SIP), which arrange the parameters (addresses, ports, etc.) for other conversations. They are roughly analogous to FTP control connections (active mode transfers are similarly broken by NAT) and are commonly used in multimedia software such as MSN Messenger and NetMeeting.
