NGINX provides the option to configure a server as a catch-all with [server_name](http://nginx.org/en/docs/http/server_names.html) for requests that do not match any of the configured server names. This configuration works without issues for HTTP traffic.
For this reason the Ingress controller provides the flag `--default-ssl-certificate`. The secret behind this flag contains the default certificate to be used in the mentioned scenario. If this flag is not provided NGINX will use a self signed certificate.
Running without the flag `--default-ssl-certificate`:
```console
$ curl -v https://10.2.78.7:443 -k
* Rebuilt URL to: https://10.2.78.7:443/
* Trying 10.2.78.4...
* Connected to 10.2.78.7 (10.2.78.7) port 443 (#0)
<span>The page you're looking for could not be found.</span>
* Connection #0 to host 10.2.78.7 left intact
```
## SSL Passthrough
The flag `--enable-ssl-passthrough` enables SSL passthrough feature.
By default this feature is disabled
## HTTP Strict Transport Security
HTTP Strict Transport Security (HSTS) is an opt-in security enhancement specified through the use of a special response header. Once a supported browser receives this header that browser will prevent any communications from being sent over HTTP to the specified domain and will instead send all communications over HTTPS.
By default the controller redirects (301) to HTTPS if there is a TLS Ingress rule.
To disable this behavior use `hsts: "false"` in the configuration ConfigMap.
By default the controller redirects (301) to `HTTPS` if TLS is enabled for that ingress. If you want to disable that behavior globally, you can use `ssl-redirect: "false"` in the NGINX config map.
To configure this feature for specific ingress resources, you can use the `nginx.ingress.kubernetes.io/ssl-redirect: "false"` annotation in the particular resource.
When using SSL offloading outside of cluster (e.g. AWS ELB) it may be useful to enforce a redirect to `HTTPS` even when there is not TLS cert available. This can be achieved by using the `nginx.ingress.kubernetes.io/force-ssl-redirect: "true"` annotation in the particular resource.
## Automated Certificate Management with Kube-Lego
[Kube-Lego] automatically requests missing or expired certificates from [Let's Encrypt] by monitoring ingress resources and their referenced secrets. To enable this for an ingress resource you have to add an annotation:
```console
kubectl annotate ing ingress-demo kubernetes.io/tls-acme="true"
```
To setup Kube-Lego you can take a look at this [full example]. The first
version to fully support Kube-Lego is nginx Ingress controller 0.8.
To provide the most secure baseline configuration possible, nginx-ingress defaults to using TLS 1.2 and a [secure set of TLS ciphers](https://github.com/kubernetes/ingress-nginx/blob/master/docs/user-guide/nginx-configuration/configmap.md#ssl-ciphers)
The default configuration, though secure, does not support some older browsers and operating systems. For instance, 20% of Android phones in use today are not compatible with nginx-ingress's default configuration. To change this default behavior, use a [ConfigMap](https://github.com/kubernetes/ingress-nginx/blob/master/docs/user-guide/nginx-configuration/configmap.md#ssl-ciphers).
