The ip 1.10.8.9 is weird actually this ip address space is reserved by the IANA

http://www.iana.org/assignments/ipv4-address-space

Seems like some kind of program or worm is running on your machines. Try to get information
regarding who is sending what for process specific traffic sniffing try out Ultra Sniffer

http://www.gjpsoft.com/ultranetsniffer/

Also you can use tcpview from sysinternals - http://www.sysinternals.com/Utilities/TcpView.html