haproxy reverse ssl termination - ssl

Question

How can I achieve reverse SSL termination with ha proxy?
From my backend via HAproxy I need to a https enabled web service. How can I successfully proxy all traffic to that service via HAProxy?
Below results in Unable to communicate securely with peer: requested domain name does not match the server's certificate.
frontend foofront
bind 127.0.0.1:443
mode tcp
default_backend foo
backend fooback
mode tcp
balance leastconn
server foo foo.bar.com:443 check

Answer 1

With HAProxy you usually have two options for handling TLS-related scenarios. TLS Passthrough and TLS Termination.
TLS Passthrough
Looks like you're trying to do this in the example you gave.
In this mode, HAProxy does not touch traffic in any way, but is just forwarding it to the backend. When TLS is involved, that means that the backend has to have a proper certificate for a domain it's accessed from - if your HAProxy is handling traffic for myexample.com, backend servers will need to have appropriate certificates for myexample.com installed.
You can always check which certificate is served by using openssl s_client:
openssl s_client -connect localhost:443
TLS Termination
Alternatively, you can terminate TLS traffic on HAProxy itself. This will allow you to use any backend (both encrypted and unencrypted). In this case, HAProxy itself decrypts traffic for myexample.com and forwards it to backend.
In your case, configuration would look something like:
frontend foofront
bind 127.0.0.1:80
bind 127.0.0.1:443 ssl crt /path/to/cert/for/myexample.com
mode tcp
default_backend foo
backend foo
mode tcp
balance leastconn
server foo foo.bar.com:443 check ssl verify none # or verify all to enforce ssl checking
You can find more info on both approaches here.
Hope this helps.