啓動sendmail竟然需要很長時間，網上查了查，有很多人碰到類似問題，但是一般都是關掉sendmail服務或者關掉dns了事，咱們現在要用它，自然不能關掉了事，dns也不能關，關了服務器沒法解析域名
毫無疑問，sendmail去做dns lookup，並且無法lookup到域名，在等待解析超時！
這裡我的主機名叫mymachinename，裡面也指定了nameserver，應該能正常做dns解析了，既然他無法解析域名，自然這是個本地域名，難道是hosts裡面的問題，查看了一下hosts文档：
# Do not remove the following line, or various programs # that require network functionality will fail. 127.0.0.1 localhost.localdomain localhost 192.168.1.28 mymachinename
好像也沒發現啥不對的，他在解析啥呢，看看log去，找到/var/log/maillog（也可能在messages），看到如下内容：
Dec 11 14:25:01 mymachinename sendmail[22710]: starting daemon (8.13.8): SMTP+queueing@01:00:00 Dec 11 14:25:01 mymachinename sm-msp-queue[22717]: My unqualified host name (mymachinename) unknown; sleeping for retry Dec 11 14:28:08 mymachinename sendmail[22803]: My unqualified host name (mymachinename) unknown; sleeping for retry Dec 11 14:35:23 mymachinename sendmail[22944]: My unqualified host name (mymachinename) unknown; sleeping for retry Dec 11 14:35:57 mymachinename sendmail[22962]: My unqualified host name (mymachinename) unknown; sleeping for retry Dec 11 14:36:54 mymachinename sendmail[22979]: My unqualified host name (mymachinename) unknown; sleeping for retry
竟然是無法解析mymachinename，有點意思，直接去ping mymachinename自然是沒問題，突然想到好像FQDN裡面槼定域名必須用”.”結尾，難道是hosts裡面少了一個”.”，嘗試修改hosts文档：
# Do not remove the following line, or various programs # that require network functionality will fail. 127.0.0.1 localhost.localdomain localhost 192.168.1.28 mymachinename. mymachinename
啓動sendmail，刷一下就啓動了。
回頭想想，問題其實很簡單，但是在網上卻沒找到什麽好的方案，說明都挺嬾的，能繞都繞過去了。
