We have a connection between our border router and the gateway firewall through the router's ethernet port and a connection to our ISP host through the router's serial port. The serial interface is fine but the ethernet interface shows a lot of collisions. Both fwall and router ethernet interfaces are set to 10half. On the router change the speed, on the fwall if we change it to 10full the router interface keeps resetting. Any ideas what could cause it and how it can be fixed?