When an e-mail message is sent directly to an MTA such as Microsoft Exchange Server, the dot-stuffing works as expected. However, when an e-mail message goes through a Symantec Messaging Gateway appliance (formerly known as Symantec Brightmail Gateway) version 8.0.3 and above and is held either inside the Spam Quarantine or the Quarantine Incident folders and then is released to be delivered normally, the SMTP dot-stuffing does not work correctly. In other words, the incoming message before it gets received by the SMG and the message delivered to end users after it is released from the Quarantine folders are different.
There are no errors for this issue.
When SMTP dot-stuffing does not work, it is usually due to an MTA implementation not being RFC compliant. For example, JavaMail MTA, among some others, is known not to be fully compliant with dot-stuffing.
Symantec is researching this issue and this article will be updated when more information is available. There is no need to open a Support case for this issue.
Without some provision for data transparency, the character sequence "<CRLF>.<CRLF>" ends the mail text and cannot be sent by the user. In general, users are not aware of such "forbidden" sequences. To allow all user composed text to be transmitted transparently, the following procedures are used:
Before sending a line of mail text, the SMTP client checks the first character of the line. If it is a period, one additional period is inserted at the beginning of the line.
When a line of mail text is received by the SMTP server, it checks the line. If the line is composed of a single period, it is treated as the end of mail indicator. If the first character is a period and there are other characters on the line, the first character is deleted."
Imported Document ID: TECH179380
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