I've got a server running Debian 8. Yes, a pretty old one. But there's something really strange about it. I can't connect to it over HTTPS:
$ curl -sSLv https://example.com
* Trying xx.yyy.xx.yyy:443...
* Connected to example.com (xx.yyy.xx.yyy) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* CAfile: /etc/ssl/certs/ca-certificates.crt
* CApath: none
} [5 bytes data]
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
} [512 bytes data]
* OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to example.com:443
* Closing connection 0
curl: (35) OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to example.com:443
$ sslscan example.com
Version: 2.0.11
OpenSSL 1.1.1m 14 Dec 2021
Connected to xx.yyy.xx.yyy
Testing SSL server example.com on port 443 using SNI name example.com
SSL/TLS Protocols:
SSLv2 disabled
SSLv3 disabled
TLSv1.0 disabled
TLSv1.1 disabled
TLSv1.2 disabled
TLSv1.3 disabled
TLS Fallback SCSV:
Connection failed - unable to determine TLS Fallback SCSV support
TLS renegotiation:
Session renegotiation not supported
TLS Compression:
OpenSSL version does not support compression
Rebuild with zlib1g-dev package for zlib support
Heartbleed:
Supported Server Cipher(s):
Certificate information cannot be retrieved.
$ dpkg -l | grep openssl
ii openssl 1.0.1t-1+deb8u12 amd64 Secure Sockets Layer toolkit - cryptographic utility
$ cat /etc/nginx/nginx.conf | grep ssl
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
$ dpkg -l | grep nginx
ii nginx 1.6.2-5 all small, powerful, scalable web/proxy server
ii nginx-common 1.6.2-5 all small, powerful, scalable web/proxy server - common files
ii nginx-full 1.6.2-5 amd64 nginx web/proxy server (standard version)
To compare it to another Debian 8 server:
$ sslscan example2.com
Version: 2.0.11
OpenSSL 1.1.1m 14 Dec 2021
Connected to xx.xxx.xx.xxx
Testing SSL server example2.com on port 443 using SNI name example2.com
SSL/TLS Protocols:
SSLv2 disabled
SSLv3 disabled
TLSv1.0 enabled
TLSv1.1 enabled
TLSv1.2 enabled
TLSv1.3 disabled
TLS Fallback SCSV:
Server supports TLS Fallback SCSV
TLS renegotiation:
Secure session renegotiation supported
TLS Compression:
OpenSSL version does not support compression
Rebuild with zlib1g-dev package for zlib support
Heartbleed:
TLSv1.2 not vulnerable to heartbleed
TLSv1.1 not vulnerable to heartbleed
TLSv1.0 not vulnerable to heartbleed
Supported Server Cipher(s):
Preferred TLSv1.2 256 bits ECDHE-RSA-AES256-GCM-SHA384 Curve P-256 DHE 256
Accepted TLSv1.2 256 bits ECDHE-RSA-AES256-SHA384 Curve P-256 DHE 256
Accepted TLSv1.2 256 bits ECDHE-RSA-AES256-SHA Curve P-256 DHE 256
Accepted TLSv1.2 256 bits DHE-RSA-AES256-GCM-SHA384 DHE 1024 bits
Accepted TLSv1.2 256 bits DHE-RSA-AES256-SHA256 DHE 1024 bits
Accepted TLSv1.2 256 bits DHE-RSA-AES256-SHA DHE 1024 bits
Accepted TLSv1.2 256 bits DHE-RSA-CAMELLIA256-SHA DHE 1024 bits
Accepted TLSv1.2 256 bits AES256-GCM-SHA384
Accepted TLSv1.2 256 bits AES256-SHA256
Accepted TLSv1.2 256 bits AES256-SHA
Accepted TLSv1.2 256 bits CAMELLIA256-SHA
Accepted TLSv1.2 128 bits ECDHE-RSA-AES128-GCM-SHA256 Curve P-256 DHE 256
Accepted TLSv1.2 128 bits ECDHE-RSA-AES128-SHA256 Curve P-256 DHE 256
Accepted TLSv1.2 128 bits ECDHE-RSA-AES128-SHA Curve P-256 DHE 256
Accepted TLSv1.2 128 bits DHE-RSA-AES128-GCM-SHA256 DHE 1024 bits
Accepted TLSv1.2 128 bits DHE-RSA-AES128-SHA256 DHE 1024 bits
Accepted TLSv1.2 128 bits DHE-RSA-AES128-SHA DHE 1024 bits
Accepted TLSv1.2 128 bits DHE-RSA-CAMELLIA128-SHA DHE 1024 bits
Accepted TLSv1.2 128 bits AES128-GCM-SHA256
Accepted TLSv1.2 128 bits AES128-SHA256
Accepted TLSv1.2 128 bits AES128-SHA
Accepted TLSv1.2 128 bits CAMELLIA128-SHA
Preferred TLSv1.1 256 bits ECDHE-RSA-AES256-SHA Curve P-256 DHE 256
Accepted TLSv1.1 256 bits DHE-RSA-AES256-SHA DHE 1024 bits
Accepted TLSv1.1 256 bits DHE-RSA-CAMELLIA256-SHA DHE 1024 bits
Accepted TLSv1.1 256 bits AES256-SHA
Accepted TLSv1.1 256 bits CAMELLIA256-SHA
Accepted TLSv1.1 128 bits ECDHE-RSA-AES128-SHA Curve P-256 DHE 256
Accepted TLSv1.1 128 bits DHE-RSA-AES128-SHA DHE 1024 bits
Accepted TLSv1.1 128 bits DHE-RSA-CAMELLIA128-SHA DHE 1024 bits
Accepted TLSv1.1 128 bits AES128-SHA
Accepted TLSv1.1 128 bits CAMELLIA128-SHA
Preferred TLSv1.0 256 bits ECDHE-RSA-AES256-SHA Curve P-256 DHE 256
Accepted TLSv1.0 256 bits DHE-RSA-AES256-SHA DHE 1024 bits
Accepted TLSv1.0 256 bits DHE-RSA-CAMELLIA256-SHA DHE 1024 bits
Accepted TLSv1.0 256 bits AES256-SHA
Accepted TLSv1.0 256 bits CAMELLIA256-SHA
Accepted TLSv1.0 128 bits ECDHE-RSA-AES128-SHA Curve P-256 DHE 256
Accepted TLSv1.0 128 bits DHE-RSA-AES128-SHA DHE 1024 bits
Accepted TLSv1.0 128 bits DHE-RSA-CAMELLIA128-SHA DHE 1024 bits
Accepted TLSv1.0 128 bits AES128-SHA
Accepted TLSv1.0 128 bits CAMELLIA128-SHA
Server Key Exchange Group(s):
TLSv1.2 128 bits secp256r1 (NIST P-256)
SSL Certificate:
Signature Algorithm: sha256WithRSAEncryption
RSA Key Strength: 4096
Subject: example2.com
Altnames: DNS:example2.com
Issuer: R3
Not valid before: Dec 17 21:00:13 2021 GMT
Not valid after: Mar 17 21:00:12 2022 GMT
$ dpkg -l | grep openssl
ii openssl 1.0.1k-3+deb8u2 amd64 Secure Sockets Layer toolkit - cryptographic utility
$ cat /etc/nginx/nginx.conf | grep ssl
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
$ dpkg -l | grep nginx
ii nginx 1.6.2-5 all small, powerful, scalable web/proxy server
ii nginx-common 1.6.2-5 all small, powerful, scalable web/proxy server - common files
ii nginx-full 1.6.2-5 amd64 nginx web/proxy server (standard version)
What's wrong with the first server? How do I make https work?
One of the servers (in terms of
nginx) hadlisten 443 ssl, but nossl_*directives. Under such circumstances you get the symptoms described in the question. That is, an issue with one server (virtual host) was affecting the other (the rest).In the error log of the faulty server you'll see: