What is SPF(Sender Policy Framwork)?

To block the spam in the webmail, there is efficient way which is SPF except the way of filtering with experience. SPF is the way of check the email whether the origination information of email is modulated. Spammer modulate the mail header information or source to pretend a spam mail as a regular one. In other words, if the original e-mail address is test@yourdomain.com, a normal email should be sent from yourdomain.com mail server. When Test@yourdomain.com user sends an email through the other mail server, the receiving server compares between the sending server IP and yourdomain.com IP. Then, if the two IPs are not the same, the receiving server classifies this email as a spam.

What is Mail Header?

Mail Headers contain tracking information for an individual email, detailing the path a message took as it crossed mail servers. To analyze the precise information, Mail header contains the following information. In recent years, spammers have sent out e-mail in which headers are manipulated so that it is sometimes impossible to get the precise information. But mail header is still the basic data of the e-mail, so we recommend that you always check the following points. Return-Path : If the sent mail is returned, the return path is assigned with the specified return address. If the sender does not assign the return address, the sender's email address is automatically entered. However, spammers assign any unknown address which has nothing to do with the spammer’s mail address, so some users have spam emails. Reply-To : When the receiver replies with the mail, the sender assigns the receiver before sending the email. If not assigned to the specific address, the sender’s email address is usually assigned automatically. From : This is the sender’s email address. It can be manipulated, so it is hard to trust. To : This is the receiver’s address. It is easily manipulated, so if there is unknown address on the received email, that does not mean it is a spam and it must be the receiver’s email. Sometime, there are broken letters on the ‘From’ or ‘To’, but it is encoded by euc-kr or utf-8, it is not broken in real. Received : When an SMTP server accepts a message, it inserts this trace record at the top of the header (last to first). The last line is the origination of the sender and the above lines indicates the mail server going through.

The mail cannot be sent by Outlook.

When sending an e-mail in Outlook, the following errors show. Because one of the recipients was rejected by the server, the message cannot be sent. 'xxxxxx@yourdomain.com' is denied. Subject 'xxx', Account: 'xxx.yourdomain.com', Server: 'xxx.yourdomain.com', Protocol: SMTP, Server Response: '553 sorry, sorry, that domain isn't allowed relay (# 5.7.1 ) ', Port: 25, Security (SSL), server Error: 553', Error Number: 0x883CCC79 The above error occurs in the server operated by smtp authentication because 'sending mail server authentication is needed' is not selected from the Outlook setting ( Tool > Account > Mail) that For the more details, visit webmail > Outlook Settings.

Mail is broken.

If an e-mail is displayed with broken characters, most the email is written by other language. In this case, click the right of mouse on the pop-up window, you will fine encoding menu. Choose the language you use, then the email will be displayed normally.

Internet is disconnected during writing an email. Can it be recovered?

Web mail is a built-in support for auto-save feature. During the process of writing the email, it is automatically saved every 20 seconds even though you did not store the email into the draft folder in the middle of writing. Users can retrieve the e-mail which is automatically saved during the write up.

Why receiving the return mail?

The following is the codes for the returned email and the description about the codes. You can find out why the email is returned from the code descriptions. (However, the message content may vary.) 421 Server too busy. 421 4.3.2 Your IP(10.10.10.10)is filtered and this connection will be closed. You must register your IP to spammaster@yourdomain.com By SpaceLee, the Lord of mail server. 451 4.4.0 DNS resolving error. 501 5.1.8 Sender domain must exist. 550 5.7.1 ... Access denied. 550 5.7.1 ... Relaying denied. IP name lookup failed. 550 Requested action not taken: mailbox unavailable. 550 5.1.1 ... User unknown. 550 5.7.1 Unable to relay for testuser@yourdomain.com. 550 RCPT ERROR. Mailbox doesn't exist. 553 sorry, your envelope sender is in my badmailfrom list. 553 sorry, that domain isn't in my list of allowed rcpt hosts. 553 5.1.8 <uni@naver.com>... Domain of sender address uni@naver.com does not exist. 554 : Recipient address rejected: Access denied.