> Adding a domain before deploying an application will result in port mappings being set. This may cause issues for applications that use non-standard ports, as those will not be automatically detected. Please refer to the [proxy documentation](/docs/networking/proxy-management.md) for information as to how to reconfigure the mappings.
The `subdomain` is inferred from the pushed application name, while the `domain.tld` is set during initial dokku configuration. It can then be modified with `dokku domains:add-global` and `dokku domains:remove-global`. This value is used as a default TLD for all applications on a host.
If an FQDN such as `dokku.org` is used as the application name, the global virtualhost will be ignored and the resulting vhost URL for that application will be `dokku.org`.
You can optionally override this in a plugin by implementing the `nginx-hostname` plugin trigger. If the `nginx-hostname` plugin has no output, the normal hostname algorithm will be executed. See the [plugin trigger documentation](/docs/development/plugin-triggers.md#nginx-hostname) for more information.
On subsequent deploys, the nginx virtualhost will be discarded. This is useful when deploying internal-facing services that should not be publicly routeable. As of 0.4.0, nginx will still be configured to proxy your app on some random high port. This allows internal services to maintain the same port between deployments. You may change this port by setting `DOKKU_PROXY_PORT` and/or `DOKKU_PROXY_SSL_PORT` (for services configured to use SSL.)
The domains plugin allows you to specify custom domains for applications. This plugin is aware of any ssl certificates that are imported via `certs:add`. Be aware that disabling domains (with `domains:disable`) will override any custom domains.
This is specific to your proxy plugin of choice. See the [nginx documentation](/docs/networking/proxies/nginx.md#default-site) for more information on how to configure this for the default nginx proxy implementation.
