Can my DCS-6111 be installed and work if a firewall exists in the network?

If a firewall exists in the network, port 80 is open for ordinary data communication and port 443 for HTTPS. The DCS-6111 uses RTSP port 554, RTP port 556, and RTP port 558 for streaming audio and video. These ports (or the ports you have specified in the Setup Tab in the Configuration screen) needs to be opened on the firewall.