系统日志的一个问题。谢谢

一个学生

我安装了一台小机
在系统日志里有很多如下信息。
请问：
1，什么原因导致的？
2，系统现在正常，会对那些服务或应用产生影响
3，谢谢

Sep 21 16:05:22 phoenix sendmail[13334]: My unqualified host name (phoenix) unknown; sleeping for retry
Sep 21 16:06:22 phoenix sendmail[13334]: unable to qualify my own domain name (phoenix) -- using short name
Sep 21 16:11:09 phoenix sendmail[13422]: My unqualified host name (phoenix) unknown; sleeping for retry
Sep 21 16:12:09 phoenix sendmail[13422]: unable to qualify my own domain name (phoenix) -- using short name
Sep 22 03:29:41 phoenix sendmail[15358]: My unqualified host name (phoenix) unknown; sleeping for retry
Sep 22 03:30:41 phoenix sendmail[15358]: unable to qualify my own domain name (phoenix) --