几天前，Gmail突然决定停止向我的邮件服务器发送邮件。我正在将Postfix和Dovecot与在所有更新的Debian 7上运行的付费SSL证书一起使用。
我mail.log显示了以下错误：
Dec 19 11:09:11 server postfix/smtpd[19878]: initializing the server-side TLS engine
Dec 19 11:09:11 server postfix/tlsmgr[19880]: open smtpd TLS cache btree:/var/lib/postfix/smtpd_scache
Dec 19 11:09:11 server postfix/tlsmgr[19880]: tlsmgr_cache_run_event: start TLS smtpd session cache cleanup
Dec 19 11:09:11 server postfix/smtpd[19878]: connect from mail-wi0-x230.google.com[2a00:1450:400c:c05::230]
Dec 19 11:09:11 server postfix/smtpd[19878]: setting up TLS connection from mail-wi0-x230.google.com[2a00:1450:400c:c05::230]
Dec 19 11:09:11 server postfix/smtpd[19878]: mail-wi0-x230.google.com[2a00:1450:400c:c05::230]: TLS cipher list "aNULL:-aNULL:ALL:+RC4:@STR ENGTH:!aNULL:!DES:!3DES:!MD5:!DES+MD5:!RC4:!RC4-MD5"
Dec 19 11:09:11 server postfix/smtpd[19878]: SSL_accept:before/accept initialization
Dec 19 11:09:11 server postfix/smtpd[19878]: SSL_accept:error in unknown state
Dec 19 11:09:11 server postfix/smtpd[19878]: SSL_accept error from mail-wi0-x230.google.com[2a00:1450:400c:c05::230]: -1
Dec 19 11:09:11 server postfix/smtpd[19878]: warning: TLS library problem: 19878:error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol:s23_srvr.c:647:
Dec 19 11:09:11 server postfix/smtpd[19878]: lost connection after STARTTLS from mail-wi0-x230.google.com[2a00:1450:400c:c05::230]
Dec 19 11:09:11 server postfix/smtpd[19878]: disconnect from mail-wi0-x230.google.com[2a00:1450:400c:c05::230]
我的后缀摘录main.cf：
smtpd_use_tls=yes
smtpd_tls_security_level = may
smtpd_tls_auth_only = yes
smtpd_tls_CAfile = path to CA Bundle
smtpd_tls_cert_file= path to cert (pem)
smtpd_tls_key_file=path to key (pem)
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_tls_mandatory_protocols = !SSLv2,!SSLv3,!TLSv1,!TLSv1.1
smtpd_tls_exclude_ciphers = aNULL, DES, 3DES, MD5, DES+MD5, RC4, RC4-MD5
smtpd_tls_protocols=!SSLv2,!TLSv1,!TLSv1.1,!SSLv3
smtpd_tls_mandatory_ciphers = medium
smtpd_tls_received_header = yes
tls_preempt_cipherlist = yes
tls_medium_cipherlist = AES256+EECDH:AES256+EDH
我不知道问题出在哪里，因为我经常收到别人的邮件。通过telnet连接到端口25或通过openssl连接到端口465没有错误
另外： 我从Google那里得到了这封邮件：
Delivery to the following recipient failed permanently:
<removed>
Technical details of permanent failure:
TLS Negotiation failed
----- Original message -----
[...]
也许是我的密码列表存在问题？
回答masegaloeh的问题：
openssl s_client -connect localhost:25 -starttls smtp
CONNECTED(00000003)
depth=3 C = SE, O = AddTrust AB, OU = AddTrust External TTP Network, CN = AddTrust External CA Root
verify error:num=19:self signed certificate in certificate chain
verify return:0
---
Certificate chain
[...]
---
Server certificate
-----BEGIN CERTIFICATE-----
[...]
---
No client certificate CA names sent
---
SSL handshake has read 6267 bytes and written 477 bytes
---
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES256-GCM-SHA384
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: zlib compression
Expansion: zlib compression
SSL-Session:
Protocol : TLSv1.2
Cipher : ECDHE-RSA-AES256-GCM-SHA384
Session-ID: [...]
Session-ID-ctx:
Master-Key: [...]
Key-Arg : None
PSK identity: None
PSK identity hint: None
SRP username: None
TLS session ticket lifetime hint: 3600 (seconds)
TLS session ticket: [...]
Compression: 1 (zlib compression)
Start Time: 1418986680
Timeout : 300 (sec)
Verify return code: 19 (self signed certificate in certificate chain)
---
250 DSN
更新1：
重新发布我的SSL证书。生成的所有内容如下：
openssl req -nodes -newkey rsa:2048 -keyout myserver.key -out server.csr -sha256
然后，我创建了一个由crt和组成的新文件key，之后创建了CA捆绑包：
cat COMODORSADomainValidationSecureServerCA.crt COMODORSAAddTrustCA.crt AddTrustExternalCARoot.crt > bundle.crt
将所有内容添加到我的dovecot和postfix配置中，然后重新启动了这两个服务。
Google仍然无法通过我的服务器发送邮件，导致TLS Negotiation failed
我尝试了另一个邮件提供商（web.de），然后邮件被发送。
web.de日志：
Dec 19 17:33:15 server postfix/smtpd[14105]: connect from mout.web.de[212.227.15.3]
Dec 19 17:33:15 server postfix/smtpd[14105]: setting up TLS connection from mout.web.de[212.227.15.3]
Dec 19 17:33:15 server postfix/smtpd[14105]: mout.web.de[212.227.15.3]: TLS cipher list "aNULL:-aNULL:ALL:+RC4:@STRENGTH"
Dec 19 17:33:15 server postfix/smtpd[14105]: mout.web.de[212.227.15.3]: save session EA1635ED786AFC2D9C7AB43EF43620A1D9092DC640FDE21C01E7BA25981D2445&s=smtp&l=268439647 to smtpd cache
Dec 19 17:33:15 server postfix/tlsmgr[14107]: put smtpd session id=EA1635ED786AFC2D9C7AB43EF43620A1D9092DC640FDE21C01E7BA25981D2445&s=smtp&l=268439647 [data 127 bytes]
Dec 19 17:33:15 server postfix/tlsmgr[14107]: write smtpd TLS cache entry EA1635ED786AFC2D9C7AB43EF43620A1D9092DC640FDE21C01E7BA25981D2445&s=smtp&l=268439647: time=1419006795 [data 127 bytes]
Dec 19 17:33:15 server postfix/smtpd[14105]: Anonymous TLS connection established from mout.web.de[212.227.15.3]: TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)
解决方法：
启用后TLSv1，TLSv1.1在本smtpd_(mandatory)_protocols节中，一切正常。谢谢masegaloeh！
Dec 20 11:44:46 server postfix/smtpd[31966]: initializing the server-side TLS engine
Dec 20 11:44:46 server postfix/tlsmgr[31968]: open smtpd TLS cache btree:/var/lib/postfix/smtpd_scache
Dec 20 11:44:46 server postfix/tlsmgr[31968]: tlsmgr_cache_run_event: start TLS smtpd session cache cleanup
Dec 20 11:44:46 server postfix/smtpd[31966]: connect from mail-wi0-x235.google.com[2a00:1450:400c:c05::235]
Dec 20 11:44:46 server postfix/smtpd[31966]: setting up TLS connection from mail-wi0-x235.google.com[2a00:1450:400c:c05::235]
Dec 20 11:44:46 server postfix/smtpd[31966]: mail-wi0-x235.google.com[2a00:1450:400c:c05::235]: TLS cipher list "aNULL:-aNULL:ALL:+RC4:@STRENGTH"
Dec 20 11:44:46 server postfix/smtpd[31966]: Anonymous TLS connection established from mail-wi0-x235.google.com[2a00:1450:400c:c05::235]: TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)
将其添加到我的问题@masegaloeh
—
Octfx 2014年
这也影响了我的进出口。好问题。
—
博伊德·史密斯·史密斯
这刚刚开始影响我，我的main.cf中没有tls_protocol行，并且记录的默认设置是仅禁用SSL2 / 3。但是下面的答案解决了我的问题。
—
Bwooce '17
openssl s_client -connect localhost:25 -starttls smtp什么？