The Telnet proxy in 602 Lan Suite 2004.0.04.0909 and earlier allows remote attackers to cause a denial of service (socket exhaustion) via a Telnet request to an IP address of the proxy's network interface, which causes a loop.
The webmail service in 602 Lan Suite 2004.0.04.0909 and earlier allows remote attackers to cause a denial of service (CPU and memory consumption) by sending a POST request with a large Content-Length value, then disconnecting without sending that amount of data.
The Telnet proxy of 602Pro LAN SUITE 2002 does not restrict the number of outstanding connections to the local host, which allows remote attackers to create a denial of service (memory consumption) via a large number of connections.