Smtp Commands - Operations - F-SECURE INTERNET GATEKEEPER FOR LINUX 4.01 Administrator's Manual

11.9 SMTP Commands – Operations
During SMTP connections, commands executed from clients are operated in the following way.
The [Product name] is by default "F-Secure/fsigk_smtp/Version/Host name".
You can change the product name by editing "product_name=" (see expert options for details).
Client connections
1 Connects to the server.
2 If the server access fails:
① The following is sent to the client: 421 server open error([Server host]:[Server port])
errmsg=[connection error message]
For connection error messages, see
", 162.
② The session ends.
3 Receives a response from the server.
4 If the response code is other than 220, the connection is terminated.
5 The following is sent to the client: 200 [Host name] [Product name]
Command-lines
1 If a line is greater than 9998 bytes:
① The following is sent to the client: 500 Too long line ([Product name])
② The connection is terminated.
2 If the following conditions are met, and a command other than HELO, EHLO, AUTH, QUIT, RSET
is received:
• POP-before-SMTP or SMTP authentication is enabled
• Authentication is not successful
• The connection is not from the LAN
• Recipient domain restrictions are not applied
① The following is sent to the client: 500 Authentication Required ([Product name])
3 If 1 and 2 above do not apply, the command is executed.
HELO command
1 The following is sent to the server: HELO [Host name]
2 Receives a response from the server.
3 The following is sent to the client: [Server response information]
F-Secure Internet Gatekeeper for Linux/Administrator's Guide
"Connection Error Messages
151