问题

1.测试邮件插件时，提示：

Paste_Image.png

2. 重新部署，只安装emailer插件后，还是提示有错

Caused: javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25;

问题排查

1.重新安装环境后，确保了jenkins是干净的，而任然不工作
2.查看iptables

service iptables status

iptables: Firewall is not running.

3.用telnet进行检查25端口

telnet localhost 25

Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused

4.进一点检查25端口，没有返回

lsof -i tcp:25

解决

初步确认是centOs的smtp服务不可用
1.安装postfix

yum -y install postfix

2.启动

postfix start

3.其它命令（stop, reload, abort, flush, check, status）

检测

telnet localhost 25

Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 7-19.localdomain ESMTP Postfix

lsof -i tcp:25

COMMAND  PID    USER   FD   TYPE   DEVICE SIZE/OFF NODE NAME
master  8162    root   12u  IPv4 52777399      0t0  TCP localhost:smtp (LISTEN)
smtpd   8309 postfix    6u  IPv4 52777399      0t0  TCP localhost:smtp (LISTEN)