2. If you want to reply a message to the "Sender" in person, Please open a new mail and put the
sender as the recipient.
如果您想要私下回覆讯息至原发信人时,请重开一新邮件,并将该发信人的邮寄地址放至收件人处后发件。
3. In these cases, ICMP sends the
sender a destination unreachable message, which indicates that the datagram could not be forwarded.
在这些案例中,ICMP传送给传送端一个目的地不能到达的讯息,它指示资料元无法转送。