如何在Docker上使用sendmail

我在Docker上使用与本地configuration相同的sendmail,但是docker始终引发拒绝连接

echo "Subject: sendmail test" | sendmail -v xxx@mail.com 

结果

 Connecting to [127.0.0.1] via relay... Deferred: Connection refused by [127.0.0.1] 

端口:

 0.0.0.0:25->25/tcp, 0.0.0.0:80->80/tcp, 0.0.0.0:587->587/tcp