通過CentOS 6系統自帶的rpm包安裝postfix之後，執行mail -s...測試發信無法成功。maillog如下：
May 29 10:44:04 cl101 postfix/pickup[31536]: BA5662A0AFC: uid=0 from=<root>
May 29 10:44:04 cl101 postfix/cleanup[31559]: BA5662A0AFC: message-id=<[email protected]>
May 29 10:44:04 cl101 postfix/qmgr[31537]: BA5662A0AFC: from=<[email protected]>, size=3431896, nrcpt=1 (queue active)
May 29 10:44:04 cl101 postfix/smtp[31561]: fatal: unknown service: smtp/tcp
May 29 10:44:05 cl101 postfix/qmgr[31537]: warning: private/smtp socket: malformed response
May 29 10:44:05 cl101 postfix/qmgr[31537]: warning: transport smtp failure -- see a previous warning/fatal/panic logfile record for the problem description
May 29 10:44:05 cl101 postfix/master[31534]: warning: process /usr/libexec/postfix/smtp pid 31561 exit status 1
May 29 10:44:05 cl101 postfix/master[31534]: warning: /usr/libexec/postfix/smtp: bad command startup -- throttling
May 29 10:44:05 cl101 postfix/error[31562]: BA5662A0AFC: to=<[email protected]>, relay=none, delay=1.3, delays=0.23/1/0/0.02, dsn=4.3.0, status=deferred (unknown mail transport error)
這是由於postfix無法讀取service文件所致。查看service的權限為640：
[root@cl101 etc]# ll|grep services
-rw-r-----. 1 root root 641243 Nov 7 2012 services
於是將其改為644：
[root@cl101 etc]# ll|grep services
-rw-r--r--. 1 root root 641243 Nov 7 2012 services
然後重試，即可解決此問題。
更多CentOS相關信息見CentOS 專題頁面 http://www.linuxidc.com/topicnews.aspx?tid=14
