Communication Ports & Protocols

VIA3 uses standard communication protocols, however all data content is encrypted from end-to-end, making the payload of the network packets opaque to any network monitoring. The VIA3 client makes only outbound requests to the VIA3 servers; no inbound connection requests are made. For those environments requiring outbound access control, the VIA3 network resides in subnet 12.129.12.128/25.

Protocols

VIA3 uses SIP (Session Initiation Protocol) for much of the communication between the clients and the servers. VIA3 uses User Datagram Protocol (UDP) or Transmission Control Protocol (TCP) for real-time data streams (audio, video, etc) where the loss of a data packet is not critical and retransmission of the missing data would cause unacceptable latency. For data transfers where loss of a data packet is unacceptable (file transfers, IM, Chat, etc), TCP is used.

Ports

The VIACK software is designed to use standard ports and protocols. In the event that some of the ports or protocols are blocked, the software will attempt to utilize other standard ports. VIA3 makes outbound connections to port 5061 (for login, presence and availability status messages, Instant Messaging (IM), meeting invitations, 5004 for real-time data streams (audio, video, mouse pointer, etc), and port 443 and 80 for other traffic. As mentioned above, if the port or protocol is blocked, VIA3 will fall back to another port or protocol. For example, when a real-time audio stream is opened, the VIA3 client attempts to connect to the server using UDP over port 5004. If the UDP connection attempt fails, the client tries TCP over the same port. If the TCP connection fails over that port, the system will connect over port 80 and 443.

VIA3 uses the following ports (TCP 443 and 80 will be used if these are not available)

TCP port 5061—SIP/SSL traffic
UDP port 5004—Audio\video traffic
TCP port 5004—Desktop sharing connections
TCP port 80—SOAP traffic

Proxy Authentication

VIA3 queries the Internet Explorer connections settings to determine the network path to the Web Proxy server. VIA3 is compatible with NTLM, Basic, and Digest authentication requests.