A method for exchanging information between computers from different computer networks without any direct connection is disclosed. The two networks include corresponding bridge computers that which share a file system residing on a common storage device. Any computer of a network needing to transmit information to a computer on the other network can map the file system of the corresponding bridge computer. The computer authenticates itself on the bridge computer, and it is then allowed to write the information into a file residing on the shared memory device. Likewise, any computer on the other network can map the same file system of the corresponding bridge computer. The computer authenticates itself on the bridge computer, and it is then allowed to read the information from a mirror copy of the file on the shared memory device. As a result, any network that is isolated from the outside can send and receive information. Such operation is possible even in the presence of virus infections without any security exposure.