我知道这个主题还有一些其他问题（及其答案）。但这些对我都没有帮助。
我有一个Postfix服务器（后缀 3.4.14Debian 10(Buster)) 具有以下配置（仅有趣的部分）：
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtp_tls_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtpd_tls_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1
smtpd_tls_exclude_ciphers = aNULL, LOW, EXP, MEDIUM, ADH, AECDH, MD5, DSS, ECDSA,
CAMELLIA128, 3DES, CAMELLIA256, RSA+AES, eNULL
smtp_tls_exclude_ciphers = aNULL, LOW, EXP, MEDIUM, ADH, AECDH, MD5, DSS, ECDSA,
CAMELLIA128, 3DES, CAMELLIA256, RSA+AES, eNULL
tls_preempt_cipherlist = yes
tls_high_cipherlist = !aNULL:!eNULL:!CAMELLIA:HIGH:@STRENGTH
如果我检查配置OpenSSL，我得到（请注意，我已经用“xxxxxx.de”使域名无法识别）：
#> openssl s_client -connect xxxxxx.de:25 -starttls smtp
CONNECTED(00000003)
depth=3 O = Digital Signature Trust Co., CN = DST Root CA X3
verify return:1
depth=2 C = US, O = Internet Security Research Group, CN = ISRG Root X1
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = R3
verify return:1
depth=0 CN = xxxxxx.de
verify return:1
---
Certificate chain
0 s:/CN=xxxxxx.de
i:/C=US/O=Let's Encrypt/CN=R3
1 s:/C=US/O=Let's Encrypt/CN=R3
i:/C=US/O=Internet Security Research Group/CN=ISRG Root X1
2 s:/C=US/O=Internet Security Research Group/CN=ISRG Root X1
i:/O=Digital Signature Trust Co./CN=DST Root CA X3
---
Server certificate
-----BEGIN CERTIFICATE-----
MIIFRjCCBC6gAwIBAgISA6SNmc1MPKtxwSiNNKEvxc/EMA0GCSqGSIb3DQEBCwUA
MDIxCzAJBgNVBAYTAlVTMRYwFAYDVQQKEw1MZXQncyBFbmNyeXB0MQswCQYDVQQD
...
...
...
VG2iG8sEGCcgG4w1LnWTO4tMlCYFE+tcXxAfE/7pB/VjmvRZlLCypanuwBzVRw5W
bPwabUtCMRDrRlT8wI9UHAhQYTb5Hhm0F0u1hi6e/7fybK6tuFnPpWs/vgT3Z4Fj
2onoaTHk/rKlhQ==
-----END CERTIFICATE-----
subject=/CN=xxxxxx.de
issuer=/C=US/O=Let's Encrypt/CN=R3
---
No client certificate CA names sent
Peer signing digest: SHA256
Server Temp Key: ECDH, P-256, 256 bits
---
SSL handshake has read 4950 bytes and written 450 bytes
---
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES256-GCM-SHA384
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
Protocol : TLSv1.2
Cipher : ECDHE-RSA-AES256-GCM-SHA384
Session-ID: B20E725616C98083988847B90FB42BFDCAEED745129C53E79E723692C641F6F5
Session-ID-ctx:
Master-Key: A3D2C497E11E47C6260C119E47DC3B4CAA119485EAFA5BCF6CDA882F115D80E78960C802A48E375DAA293A3A2C1DAE35
Key-Arg : None
Krb5 Principal: None
PSK identity: None
PSK identity hint: None
TLS session ticket lifetime hint: 7200 (seconds)
TLS session ticket:
0000 - ec 40 39 d6 f4 94 ac 7b-d8 f8 ef 94 98 62 d7 35 .@9....{.....b.5
0010 - de fb c3 f5 f3 b1 3a d1-24 3e 62 57 fb 06 56 eb ......:.$>bW..V.
0020 - 84 61 2a 0d 30 7d 9f ac-70 e7 a8 a3 23 4a c6 57 .a*.0}..p...#J.W
0030 - dc 21 7c d3 5d f4 e8 14-c5 4c 18 da 35 1d 32 49 .!|.]....L..5.2I
0040 - f0 19 de 75 77 22 25 f9-74 4d a2 47 39 0d ce 75 ...uw"%.tM.G9..u
0050 - 0a 04 41 85 0d 67 05 fe-a4 09 ec 72 4b a5 ad f4 ..A..g.....rK...
0060 - 8b 73 a2 a3 2e 28 46 b8-2a 60 4b ed ce 75 09 fb .s...(F.*`K..u..
0070 - ef 95 e3 e2 6e 6a 90 bd-9e 46 e8 c9 aa 52 c3 ae ....nj...F...R..
0080 - 72 6f 9f 37 fd 6c 12 e9-bb 60 83 c6 c4 44 ca 85 ro.7.l...`...D..
0090 - cb ee 1d bd 69 29 77 31-4f 96 d5 4d 93 8e 63 d2 ....i)w1O..M..c.
Start Time: 1623221077
Timeout : 300 (sec)
Verify return code: 0 (ok)
---
250 CHUNKING
我在这里想知道这条线
New, TLSv1/SSLv3, Cipher is ECDHE-RSA-AES256-GCM-SHA384
因为 TLSv1/SSLv3 应通过 postfix 配置禁用。可能是这个问题吗？
然而。在客户端我有一个 Java 应用程序（OpenJDK11.0.11），每次我发送电子邮件时，我都会收到：
javax.mail.MessagingException: Could not convert socket to TLS;
nested exception is:
javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
at com.sun.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:1907)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:666)
at javax.mail.Service.connect(Service.java:295)
...
当然，我已经编辑好了conf/security/java.security文件。我已经添加了ECDHE-RSA-AES256-GCM-SHA384 as jdk.tls.legacyAlgorithms。以下是有趣的设置java.securtity:
jdk.tls.legacyAlgorithms= \
K_NULL, C_NULL, M_NULL, \
DH_anon, ECDH_anon, \
RC4_128, RC4_40, DES_CBC, DES40_CBC, \
3DES_EDE_CBC, ECDHE-RSA-AES256-GCM, ECDHE-RSA-AES256-GCM-SHA384
jdk.certpath.disabledAlgorithms=MD2, MD5, SHA1 jdkCA & usage TLSServer, \
RSA keySize < 1024, DSA keySize < 1024, EC keySize < 224, \
include jdk.disabled.namedCurves
jdk.tls.disabledAlgorithms=SSLv3, TLSv1, TLSv1.1, RC4, DES, MD5withRSA, \
DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, \
include jdk.disabled.namedCurves
也许我是瞎子，但我不知道我的问题在哪里......
好的，首先我已经删除了我的扩展jdk.tls.legacyAlgorithms，因为这些没有帮助而且是错误的（感谢 dave_thompson_085 的提示）。
以下是用于发送电子邮件的 Java 代码（该代码具有“悠久”的历史，所以请不要奇怪为什么会有Vector代替ArrayList大概用过...）
// Create some properties and get the default Session
Properties props = new Properties();
props.put("mail.smtp.host", smtpServer);
props.put("mail.smtp.port", "25");
props.put("mail.debug", "true");
// SMTP authentication?
Session session;
if (username != null && pwd != null && username.length() > 0 && pwd.length() > 0) {
props.put("mail.smtp.auth", "true");
//props.put("mail.smtp.user", username);
//props.put("mail.password", pwd);
// if SMTP authentication: use TLS in every case!
tls = true;
session = Session.getInstance(props, new MyPasswordAuthenticator(username, pwd));
} else {
session = Session.getDefaultInstance(props, null);
}
// TLS?
if (tls) {
props.put("mail.smtp.starttls.enable", "true");
//props.put("mail.smtp.tls", "true");
}
// create a message
SMTPMessage mimeMsg = new SMTPMessage(session);
InternetAddress addressFrom = new InternetAddress(sender);
mimeMsg.setFrom(addressFrom);
mimeMsg.setEnvelopeFrom(sender);
// Set recipients ...
InternetAddress[] tos = new InternetAddress[receivers.size()];
int i = 0;
for (String addr : receivers) {
tos[i++] = new InternetAddress(addr, extractPersonalNameFromEMailAddr(addr));
}
// Set CC recipients ...
InternetAddress[] ccAddrs = new InternetAddress[0];
if (ccs != null) {
ccAddrs = new InternetAddress[ccs.size()];
i = 0;
for (String addr : ccs) {
ccAddrs[i++] = new InternetAddress(addr, extractPersonalNameFromEMailAddr(addr));
}
}
mimeMsg.setRecipients(Message.RecipientType.TO, tos);
mimeMsg.setRecipients(Message.RecipientType.CC, ccAddrs);
// Set return notifications
if (readNotificationRequest) {
String notifyAddr = replyTo;
if (notifyAddr == null || notifyAddr.trim().length() == 0) notifyAddr = sender;
mimeMsg.addHeader("Disposition-Notification-To", "<" + notifyAddr + ">");
mimeMsg.addHeader("Return-Receipt-To", "<" + notifyAddr + ">");
}
mimeMsg.addHeader("Date", mailDateFormat.format(new Date()));
mimeMsg.setNotifyOptions(deliverNotificationRequest);
mimeMsg.setReturnOption(deliverNotificationContent);
if (replyTo != null) {
Address[] replyToAddrs = new Address[1];
replyToAddrs[0] = new InternetAddress(this.replyTo);
mimeMsg.setReplyTo(replyToAddrs);
mimeMsg.setFrom(replyToAddrs[0]);
}
mimeMsg.setSentDate(new Date());
mimeMsg.setSubject(subject);
//mimeMsg.setContent(msg, msgType);
// Set the text content:
MimeBodyPart msgPart = new MimeBodyPart();
msgPart.setContent(msg, msgType + "; charset=" + charset);
Multipart multipart = new MimeMultipart();
multipart.addBodyPart(msgPart);
// Add the attachments:
String attFile;
MimeBodyPart attachment;
Iterator<String> it = new Vector<String>(attachments).iterator();
while (it.hasNext()) {
attFile = it.next();
attachment = new MimeBodyPart();
attachment.setDataHandler(new DataHandler(new AppOctetStreamFileDataSource(attFile)));
attachment.setFileName(FileUtil.extractFilename(attFile));
multipart.addBodyPart(attachment);
}
mimeMsg.setContent(multipart);
System.out.println("mail.smtp.ssl.trust: <<" + System.getProperty("mail.smtp.ssl.trust") + ">>");
System.out.println("mail.smtp.ssl.socketfactory.class: <<" + System.getProperty("mail.smtp.ssl.socketfactory.class") + ">>");
System.out.println("mail.smtp.socketfactory.class: <<" + System.getProperty("mail.smtp.socketfactory.class") + ">>");
System.out.println("mail.smtp.ssl.protocols: <<" + System.getProperty("mail.smtp.ssl.protocols") + ">>");
System.out.println("mail.smtp.ssl.ciphersuites: <<" + System.getProperty("mail.smtp.ssl.ciphersuites") + ">>");
System.out.println("SSLContext.getDefault().getDefaultSSLParameters().getProtocols(): "
+ Arrays.toString(SSLContext.getDefault().getDefaultSSLParameters().getProtocols()));
System.out.println("Arrays.toString(SSLContext.getDefault().getDefaultSSLParameters().getCipherSuites(): "
+ Arrays.toString(SSLContext.getDefault().getDefaultSSLParameters().getCipherSuites()));
session.setDebug(debug);
Transport transport = session.getTransport("smtp");
transport.connect(smtpServer, 25, username, pwd);
//System.out.println("#########" + System.getProperty("mail.smtp.localhost"));
transport.sendMessage(mimeMsg, mimeMsg.getAllRecipients());
transport.close();
为了调试，我添加了一些 System.out 来输出一些有趣的值。
这里是标准输出：
DEBUG: JavaMail version 1.4.7
DEBUG: successfully loaded resource: /META-INF/javamail.default.providers
DEBUG: Tables of loaded providers
DEBUG: Providers Listed By Class Name: {com.sun.mail.smtp.SMTPSSLTransport=javax.mail.Provider[TRANSPORT,smtps,com.sun.mail.smtp.SMTPSSLTransport,Oracle], com.sun.mail.smtp.SMTPTransport=javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Oracle], com.sun.mail.imap.IMAPSSLStore=javax.mail.Provider[STORE,imaps,com.sun.mail.imap.IMAPSSLStore,Oracle], com.sun.mail.pop3.POP3SSLStore=javax.mail.Provider[STORE,pop3s,com.sun.mail.pop3.POP3SSLStore,Oracle], com.sun.mail.imap.IMAPStore=javax.mail.Provider[STORE,imap,com.sun.mail.imap.IMAPStore,Oracle], com.sun.mail.pop3.POP3Store=javax.mail.Provider[STORE,pop3,com.sun.mail.pop3.POP3Store,Oracle]}
DEBUG: Providers Listed By Protocol: {imaps=javax.mail.Provider[STORE,imaps,com.sun.mail.imap.IMAPSSLStore,Oracle], imap=javax.mail.Provider[STORE,imap,com.sun.mail.imap.IMAPStore,Oracle], smtps=javax.mail.Provider[TRANSPORT,smtps,com.sun.mail.smtp.SMTPSSLTransport,Oracle], pop3=javax.mail.Provider[STORE,pop3,com.sun.mail.pop3.POP3Store,Oracle], pop3s=javax.mail.Provider[STORE,pop3s,com.sun.mail.pop3.POP3SSLStore,Oracle], smtp=javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Oracle]}
DEBUG: successfully loaded resource: /META-INF/javamail.default.address.map
mail.smtp.ssl.trust: <<null>>
mail.smtp.ssl.socketfactory.class: <<null>>
mail.smtp.socketfactory.class: <<null>>
mail.smtp.ssl.protocols: <<null>>
mail.smtp.ssl.ciphersuites: <<null>>
SSLContext.getDefault().getDefaultSSLParameters().getProtocols(): [TLSv1.3, TLSv1.2]
Arrays.toString(SSLContext.getDefault().getDefaultSSLParameters().getCipherSuites(): [TLS_AES_128_GCM_SHA256, TLS_AES_256_GCM_SHA384, TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, TLS_RSA_WITH_AES_256_GCM_SHA384, TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384, TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384, TLS_DHE_RSA_WITH_AES_256_GCM_SHA384, TLS_DHE_DSS_WITH_AES_256_GCM_SHA384, TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, TLS_RSA_WITH_AES_128_GCM_SHA256, TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256, TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256, TLS_DHE_RSA_WITH_AES_128_GCM_SHA256, TLS_DHE_DSS_WITH_AES_128_GCM_SHA256, TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384, TLS_RSA_WITH_AES_256_CBC_SHA256, TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384, TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384, TLS_DHE_RSA_WITH_AES_256_CBC_SHA256, TLS_DHE_DSS_WITH_AES_256_CBC_SHA256, TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, TLS_RSA_WITH_AES_256_CBC_SHA, TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA, TLS_ECDH_RSA_WITH_AES_256_CBC_SHA, TLS_DHE_RSA_WITH_AES_256_CBC_SHA, TLS_DHE_DSS_WITH_AES_256_CBC_SHA, TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256, TLS_RSA_WITH_AES_128_CBC_SHA256, TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256, TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256, TLS_DHE_RSA_WITH_AES_128_CBC_SHA256, TLS_DHE_DSS_WITH_AES_128_CBC_SHA256, TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, TLS_RSA_WITH_AES_128_CBC_SHA, TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA, TLS_ECDH_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_DSS_WITH_AES_128_CBC_SHA, TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
和标准错误：
javax.net.ssl|DEBUG|01|main|2021-06-10 08:28:39.042 CEST|SSLCipher.java:438|jdk.tls.keyLimits: entry = AES/GCM/NoPadding KeyUpdate 2^37. AES/GCM/NOPADDING:KEYUPDATE = 137438953472
javax.net.ssl|ERROR|01|main|2021-06-10 08:28:39.306 CEST|TransportContext.java:341|Fatal (HANDSHAKE_FAILURE): Couldn't kickstart handshaking (
"throwable" : {
javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
at java.base/sun.security.ssl.HandshakeContext.(HandshakeContext.java:170)
at java.base/sun.security.ssl.ClientHandshakeContext.(ClientHandshakeContext.java:98)
at java.base/sun.security.ssl.TransportContext.kickstart(TransportContext.java:221)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:433)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:411)
at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:549)
at com.sun.mail.util.SocketFetcher.startTLS(SocketFetcher.java:486)
at com.sun.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:1902)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:666)
at javax.mail.Service.connect(Service.java:295)
at com.coco_on.tools.general.useCases.net.UCSendEMail.start(UCSendEMail.java:470)
at com.tetrixSystems.tHiddenExecuter.Executer.start(Executer.java:233)
at com.tetrixSystems.tHiddenExecuter.UCMain.start(UCMain.java:83)
at com.tetrixSystems.tHiddenExecuter.UCMain.main(UCMain.java:49)}
)
javax.net.ssl|DEBUG|01|main|2021-06-10 08:28:39.306 CEST|SSLSocketImpl.java:1638|close the underlying socket
javax.net.ssl|DEBUG|01|main|2021-06-10 08:28:39.306 CEST|SSLSocketImpl.java:1657|close the SSL connection (initiative)
javax.mail.MessagingException: Could not convert socket to TLS;
nested exception is:
javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
at com.sun.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:1907)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:666)
at javax.mail.Service.connect(Service.java:295)
at com.coco_on.tools.general.useCases.net.UCSendEMail.start(UCSendEMail.java:470)
at com.tetrixSystems.tHiddenExecuter.Executer.start(Executer.java:233)
at com.tetrixSystems.tHiddenExecuter.UCMain.start(UCMain.java:83)
at com.tetrixSystems.tHiddenExecuter.UCMain.main(UCMain.java:49)
Caused by: javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
at java.base/sun.security.ssl.HandshakeContext.(HandshakeContext.java:170)
at java.base/sun.security.ssl.ClientHandshakeContext.(ClientHandshakeContext.java:98)
at java.base/sun.security.ssl.TransportContext.kickstart(TransportContext.java:221)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:433)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:411)
at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:549)
at com.sun.mail.util.SocketFetcher.startTLS(SocketFetcher.java:486)
at com.sun.mail.smtp.SMTPTransport.startTLS(SMTPTransport.java:1902)
... 6 more
在 Postfix 服务器端，安装了 OpenSSL 1.1.1：
#> openssl version
OpenSSL 1.1.1d 10 Sep 2019
我不相信Java在内部使用OpenSSL，但客户端openssl版本（CentOS/RHEL7）可能也很有趣：
#> openssl version
OpenSSL 1.0.2k-fips 26 Jan 2017
