前言:
新上一台阿里的云主机，提供web服务，各种环境搭建完成，能够提供服务，没想到在最后的监控环节遇到各种发邮件的坑，这里分享给大家，你是否也遇到这种坑？
网易163免费邮箱相关服务器信息：
一、安装和配置:
1.1、安装
[root@linux-node2 ~]# yum install mailx -y Loaded plugins: fastestmirror, security Setting up Install Process Determining fastest mirrors * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com base | 3.7 kB 00:00 epel | 3.2 kB 00:00 epel/primary | 3.2 MB 00:00 epel 12521/12521 extras | 3.4 kB 00:00 icehouse | 2.9 kB 00:00 updates | 3.4 kB 00:00 updates/primary_ | 1.2 MB 00:00 Package mailx-12.4-8.el6_6.x86_64 already installed and latest version Nothing to do
1.2、配置(以163邮箱为例)
首先你的邮箱要支持你的需求，到邮箱里去配置
然后到/etc/mail.rc的配置文件中去添加
set from=admin@163.com smtp=smtp.163.com smtp-auth-user=admin smtp-auth-password=xxxxxx smtp-auth=login
[root@linux-node2 ~]# echo “12345” | mail -v -s “test” admin@163.com
至此应该是没问题，但是就是收不到邮件。得了，开始排错！所有的网络、配置检查完成后，还是收不到邮件，最后检查到端口发现问题！！！
[root@linux-node2 ~]# telnet smtp.163.com 25
Trying 220.181.12.17...
^C
[root@orcherstrator ~]# nc -vz -w 1 smtp.163.com 25
nc: connect to smtp.163.com port 25 (tcp) timed out: Operation now in progress
nc: connect to smtp.163.com port 25 (tcp) timed out: Operation now in progress
nc: connect to smtp.163.com port 25 (tcp) timed out: Operation now in progress
nc: connect to smtp.163.com port 25 (tcp) timed out: Operation now in progress
nc: connect to smtp.163.com port 25 (tcp) timed out: Operation now in progress
nc: connect to smtp.163.com port 25 (tcp) timed out: Operation now in progress
nc: connect to smtp.163.com port 25 (tcp) timed out: Operation now in progress
nc: connect to smtp.163.com port 25 (tcp) timed out: Operation now in progress
原来服务器根本就不能和第三方邮箱建立连接，问题找到，开始处理，一查才知道阿里云服务器把25端口给封了，需要申请解封。好吧！登录管理控制台，开始申请！！！
阿里云的审核速度还挺快的，两个多小时后反馈结果了，不过看看就吐口老血！！！
只能想其他的办法呗！！最后决定使用163邮箱的465加密端口
[root@orcherstrator ~]# telnet smtp.163.com 465
Trying 220.181.12.14...
Connected to smtp.163.com.
Escape character is '^]'.
^C
Connection closed by foreign host.
root@orcherstrator ~]# nc -vz -w 1 smtp.163.com 465
Connection to smtp.163.com 465 port [tcp/urd] succeeded!
看样子有戏哦！！！修改/etc/mail.rc的配置
set from=admin@163.com
set smtp="smtps://smtp.163.com:465"
set smtp-auth-user=admin@163.com
set smtp-auth-password=xxxxx
set smtp-auth=login
set smtp-use-starttls
set ssl-verify=ignore
set nss-config-dir=/etc/pki/nssdb/
[root@linux-node2 ~]# echo 'hello' |mail -v -s "test" yueyuancun@163.com
Resolving host smtp.163.com . . . done.
Connecting to 123.125.50.133 . . . connected.
Error in certificate: Peer's certificate issuer is not recognized. ##没有对端的证书
Comparing DNS name: "*.163.com"
SSL parameters: cipher=AES-128-GCM, keysize=128, secretkeysize=128,
issuer=CN=GeoTrust SSL CA - G3,O=GeoTrust Inc.,C=US
subject=CN=*.163.com,O="NetEase (Hangzhou) Network Co., Ltd",L=HangZhou,ST=ZheJiang,C=CN
220 163.com Anti-spam GT for Coremail System (163com[20141201])
> EHLO linux-node2
250-mail
250-PIPELINING
250-AUTH LOGIN PLAIN
250-AUTH=LOGIN PLAIN
250-coremail 1Uxr2xKj7kG0xkI17xGrU7I0s8FY2U3Uj8Cz28x1UUUUU7Ic2I0Y2UFVHs-cUCa0xDrUUUUj
250-STARTTLS
250 8BITMIME
> AUTH LOGIN
334 dXNlcm5hbWU6
> eXVleXVhbmN1bkAxNjMuY29t
334 UGFzc3dvcmQ6
> aGVsbG9uaWhhbzE5ODkxMA==
535 Error: authentication failed
smtp-server: 535 Error: authentication failed
"/root/dead.letter" 11/299
. . . message not sent. ##邮件没有发出去
至此，网上的case都说能收到邮件，但是我这就是收不到，那就根据错误来解决呗！！！搞证书
[root@linux-node2 ~]# mkdir -p /root/.certs/
[root@linux-node2 ~]# echo -n | openssl s_client -connect smtp.163.com:465 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > ~/.certs/163.crt
depth=2 C = US, O = GeoTrust Inc., CN = GeoTrust Global CA
verify return:1
depth=1 C = US, O = GeoTrust Inc., CN = GeoTrust SSL CA - G3
verify return:1
depth=0 C = CN, ST = ZheJiang, L = HangZhou, O = "NetEase (Hangzhou) Network Co., Ltd", CN = *.163.com
verify return:1
DONE
[root@linux-node2 ~]# certutil -A -n "GeoTrust SSL CA" -t "C,," -d ~/.certs -i ~/.certs/163.crt
[root@linux-node2 ~]# certutil -A -n "GeoTrust Global CA" -t "C,," -d ~/.certs -i ~/.certs/163.crt
[root@linux-node2 ~]# certutil -L -d /root/.certs
Certificate Nickname Trust Attributes
SSL,S/MIME,JAR/XPI
GeoTrust SSL CA C,,
[root@linux-node2 ~]# cd /root/.certs/
[root@linux-node2 .certs]# certutil -A -n "GeoTrust SSL CA - G3" -t "Pu,Pu,Pu" -d ./ -i 163.crt
Notice: Trust flag u is set automatically if the private key is present.
[root@linux-node2 .certs]# cd
[root@linux-node2 ~]# vim /etc/mail.rc
set from=admin@163.com
set smtp="smtps://smtp.163.com:465"
set smtp-auth-user=admin@163.com
set smtp-auth-password=xxxxx
set smtp-auth=login
set smtp-use-starttls
set ssl-verify=ignore
set nss-config-dir=/root/.certs
[root@linux-node2 ~]# echo 'hello' |mail -v -s "test" admin@163.com
Resolving host smtp.163.com . . . done.
Connecting to 123.125.50.132 . . . connected.
Comparing DNS name: "*.163.com"
SSL parameters: cipher=AES-128-GCM, keysize=128, secretkeysize=128,
issuer=CN=GeoTrust SSL CA - G3,O=GeoTrust Inc.,C=US
subject=CN=*.163.com,O="NetEase (Hangzhou) Network Co., Ltd",L=HangZhou,ST=ZheJiang,C=CN
220 163.com Anti-spam GT for Coremail System (163com[20141201])
> EHLO linux-node2
250-mail
250-PIPELINING
250-AUTH LOGIN PLAIN
250-AUTH=LOGIN PLAIN
250-coremail 1Uxr2xKj7kG0xkI17xGrU7I0s8FY2U3Uj8Cz28x1UUUUU7Ic2I0Y2UF6b612UCa0xDrUUUUj
250-STARTTLS
250 8BITMIME
> AUTH LOGIN
334 dXNlcm5hbWU6
> eXVleXVhbmN1bkAxNjMuY29t
334 UGFzc3dvcmQ6
> aGVsbG9uaWhhbzE5ODk=
235 Authentication successful
> MAIL FROM:<admin@163.com>
250 Mail OK
> RCPT TO:<admin@163.com>
250 Mail OK
> DATA
354 End data with <CR><LF>.<CR><LF>
> .
250 Mail OK queued as smtp2,DNGowADH53eJp5BbGYUHAA--.2S2 1536206732
> QUIT
221 Bye
终于成功了！！！！
注:不管能否解决你遇到的问题，欢迎相互交流，共同提高！