1. Search the information of the mail header: the mail header is some metadata, including the sending, receiving and processing information of the mail. The message header contains the sender's IP address, mail server and other information, which can be obtained by viewing the message header.
2. Inquire through ISP or e-mail service provider: ISP or e-mail service provider can trace the source address of anonymous e-mail through logs and other means, so as to find the true identity of the sender.