loss in udp

I need to send some data over UDP (cant use TCP), and i want to make sure that the data gets there. I thought that sending som data to the other host, and then that host sends a reply back saying HEY I GOT IT, but then theres a chance that HEY I GOT IT is dropped too..

is there any way i can make sure that the receiver gets it??

You need TCP/UDP/IP.

http://www.csm.ornl.gov/~dunigan/net100/atou.html
http://thebends.org/~allen/utunnel/
http://www.jankratochvil.net/project/tcpoverudp/

Or maybe you can use an alternative to TCP and UDP like SCTP.

Or maybe you should just fucking use TCP/IP. Your reasons for not using it are irrelevant.