IPv6 working fine, IPv4 throws OpenSSL error

jippie asked:

I am building a webserver ( http://blog.linformatronics.nl/ ), which functions just fine on both IPv4 and IPv6 and when using a non-SSL connection. However when I connect to it through https, IPv6 works as expected, but an IPv4 connection throws a client side error. Server side logs are empty for the IPv4/https connection. Summarized in a table:

     | http  | https
IPv4 | works | OpenSSL error, failed. No server side logging.
IPv6 | works | self signed certificate warning, but works as expected

Apparently the SSL tunnel isn’t even set up, which accounts for the Apache logs being empty. But why does it work fine for IPv6 and fail for IPv4?
My question is why is this OpenSSL error being thrown and how can I solve it?

Below is some extra information about the setup.

IPv6 https

Command used to reproduce IPv6/https behaviour:

$ wget --no-check-certificate -O /dev/null -6 https://blog.linformatronics.nl
--2012-11-03 15:46:48--  https://blog.linformatronics.nl/
Resolving blog.linformatronics.nl (blog.linformatronics.nl)... 2001:980:1b7f:1:a00:27ff:fea6:a2e7
Connecting to blog.linformatronics.nl (blog.linformatronics.nl)|2001:980:1b7f:1:a00:27ff:fea6:a2e7|:443... connected.
WARNING: cannot verify blog.linformatronics.nl's certificate, issued by `/CN=localhost':
  Self-signed certificate encountered.
    WARNING: certificate common name `localhost' doesn't match requested host name `blog.linformatronics.nl'.
HTTP request sent, awaiting response... 200 OK
Length: 4556 (4.4K) [text/html]
Saving to: `/dev/null'

100%[=======================================================================>] 4,556       --.-K/s   in 0s      

2012-11-03 15:46:49 (62.5 MB/s) - `/dev/null' saved [4556/4556]

IPv4 https

Command used to reproduce IPv6/https behaviour:

$ wget --no-check-certificate -O /dev/null -4 https://blog.linformatronics.nl
--2012-11-03 15:47:28--  https://blog.linformatronics.nl/
Resolving blog.linformatronics.nl (blog.linformatronics.nl)...
Connecting to blog.linformatronics.nl (blog.linformatronics.nl)||:443... connected.
OpenSSL: error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol
Unable to establish SSL connection.


  • I am on Ubuntu Server 12.04.1 LTS

My answer:

You have some serious firewall/NAT misconfigurations. You aren’t actually running a web server on port 443…

$ telnet 443
Connected to
Escape character is '^]'.
SSH-2.0-OpenSSH_6.0p1 Debian-3ubuntu1

And your IPv6 service seems to be firewalled off…

$ telnet 2001:980:1b7f:1:a00:27ff:fea6:a2e7 443
Trying 2001:980:1b7f:1:a00:27ff:fea6:a2e7...
telnet: connect to address 2001:980:1b7f:1:a00:27ff:fea6:a2e7: Permission denied

Fix your firewall and/or service-on-the-wrong-port issues, and you should find things start working.

View the full question and answer on Server Fault.

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