| 摘要 |
PURPOSE:To prevent the reception of electronic mail which a caller sends from his own node by using illegally the identification name of another user by confirming the presence of the inconsistency of tracing information written at a repeating node at a final receiving node. CONSTITUTION:As for the electronic mail from a calling UA-A to a receiving UA-B, information that the electronic mail passed through is written in an envelope by a tracing information writing means on each node of MTA1 to MTA3. Then in the case that the UA-C sends the electronic mail to the UA-B by using illegally the identification name of the UA-A, the received tracing information and a received caller identification name are collated with network constitution information by a collating means on the node MTA2, and the presence of the inconsistency is confirmed. Accordingly, the inconsistency between the repeating node MTA4 and an electronic mail sending node MTA1 is detected. |
