What is mail forwarding (Mail Relay)
Skill administrator (2000-12-24 10:18) 〖Back〗 〖Forward〗
After setting an email server, the server will have one or several domain names. At this time, the Email server will listen to the No. 25 port and wait for a request for remote email. Other Mail servers on the network or request send mail MUA (Mail User Agent, such as Outlook Express, Foxmail, etc.) will connect to the Email server's 25th port, request sending mail, the SMTP session process is usually starting from remote identity of your identity The process is as follows: Helo Remote.system.domainName 250 qmailserver.domain mail from: user@somainmault.net 250 ok rcpt to: user1@elsewhere.net mail recipient user1@elsewhere.net Domain name@elsewhere.net is not necessarily a local name At this time, the local system may have two answers, accept it: 250 ok or refuse to accept it: 553 Sorry, .that domain isnot in My Domain List of allowed Recphone, the local Email server is allowed to be relay, it Receive and agreed to pass a destination address that does not belong to the local domain name; and the second case does not receive non-local mail. Email generally has a configuration file that determines whether to accept one email. The message is accepted only when the domain name of the recipient address in a RCPT TO command is present in the file, otherwise the message is rejected. If the file does not exist, all mail will be accepted. When a mail server does not care for the mail recipient and mail recipient, it is called an open forward. When the Email server does not set forwarding restrictions, it is open forward.
