如果squirremail未郵件開啓smtp認證：
用squirrelmail發送郵件時出現如下提示:
Message not sent. Server replied:
Transaction failed
554 5.7.1 <52********@qq.com>: Relay access denied
進入 squirremail目錄 /var/www/html/webmail
config/conf.pl
Main Menu --
1. Organization Preferences
2. Server Settings
3. Folder Defaults
4. General Options
5. Themes
6. Address Books
7. Message of the Day (MOTD)
8. Plugins
9. Database
10. Languages
按照提示選擇2
Server Settings
General
-------
1. Domain : localhost.localdomain
2. Invert Time : false
3. Sendmail or SMTP : SMTP
A. Update IMAP Settings : localhost:143 (dovecot)
B. Update SMTP Settings : 127.0.0.1:25
R Return to Main Menu
C Turn color on
S Save data
Q Quit
選擇B
Server Settings
General
-------
1. Domain : localhost.localdomain
2. Invert Time : false
3. Sendmail or SMTP : SMTP
SMTP Settings
-------------
4. SMTP Server : 127.0.0.1
5. SMTP Port : 25
6. POP before SMTP : false
7. SMTP Authentication : none 將這個改爲login
8. Secure SMTP (TLS) : false
9. Header encryption key :
選擇7
Command >> 7
*** YOUR SMTP SERVER MUST SUPPORT THE MECHANISM YOU CHOOSE HERE ***
If you don't understand or are unsure, you probably want "none"
none, login, cram-md5, or digest-md5 [none]: login 將none改爲login
SMTP authentication uses IMAP username and password by default.
Would you like to use other login and password for all SquirrelMail
SMTP connections? [y/N]:N
R Return to Main Menu
C Turn color on
S Save data
Q Quit
保存退出後再使用squirrelmail發送郵件就可以了。