The main characteristics of the satellite channel are large delay and bit error. Both characteristics make TCP perform poorly in satellite communication, and force optimization of TCP and even definition of new transport protocols. Using the optimized protocols only in the satellite channel complicates the use of host-to-host IPsec connections. This dissertation proposes and tests different host-to-host security solutions for such systems. The proposals use IPsec, SSL, TLS and SSH. The tests show that secure communication performs as good as insecure communication in a satellite channel. Further studies of IPsec shows that the replay window, as specified in RFC 2401, is too small when used in communication with high bandwidth and large delay. The dissertation implements a new replay mechanism with larger window. Through tests it is proved that it performs as fast as the original implementation.