# Connecting A NATS system is usually identified by a standard URL with the `nats` or `tls` protocol, e.g. nats\://demo.nats.io. A NATS system can be a single server, a small cluster or a global super cluster. Throughout these examples we will rely on a single test server, provided by [nats.io](https://nats.io), at `nats://demo.nats.io`, where `4222` is the default port for NATS. NATS also supports secure connectivity using TLS via the `tls` protocol. Most clients support auto-detection of a secure connection using the URL protocol `tls`. There is also a demo server running TLS at `tls://demo.nats.io:4443`. The protocol requirement is being made optional for many client libraries, so that you can use `demo.nats.io:4222` as the URL and let the client and server resolve whether or not TLS is required. There are numerous options for a NATS connection ranging from timeouts to reconnect settings. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://nats.golang.im/developing-with-nats/connecting.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.