Articles on: Using Quortex Play

How to choose your SRT input type?

Quortex I/O offers two input modes:

Listener (aka server mode): this is the default mode, where Quortex I/O will act as a SRT server and listen for incoming connections from your SRT clients.

Caller (aka client mode), where Quortex I/O will act as a SRT client and will initiate the connection to your SRT server.

We do not support the SRT "Rendez-Vous" mode

You may wonder what are the differences between these two modes and why you should choose one or the other. Both modes have their pros and cons. Let's find out!

Listener Mode

The key advantage of the listener mode is that your streams should natively be able to traverse firewalls located between your SRT clients and Quortex I/O, as these clients will initiate an outbound connection through the firewall towards Quortex I/O. Enterprise firewall usually accept outbound connection on any protocol and to any IP:Port and the SRT connection should not be blocked.

Your IT may have blocked UDP outbound connection on some ports an/or some protocols. Please refer to your IT admin in such a case.

UDP hole punching, which is widely deployed in any firewall, will then be leveraged in the firewall so that the traffic coming from Quortex I/O to your client can traverse this firewall.

One disadvantage of the listener mode is that Quortex I/O will allocate a dedicated "IP:Port" to listen for incoming connections. This "IP:Port" can't be known ahead of time and is fully dynamic. Consequently, you need to create your input to be able to configure your SRT client.

Quortex I/O will automatically generate a random passphrase for securing the transmission. The passphrase can be found after the wizard step, by clicking on a given input.

In case you want to further increase the security, you can allow only a specific CIDR to establish a connection to Quortex I/O. This can be done after the wizard, by editing a given input.

Caller Mode

When acting in caller (client) mode, you can make connections to any server to join streams. This can have advantages as you don't have to retrieve dynamic "IP:Port" information from Quortex I/O to establish a connection.

In this mode, the passphrase is optional and is configurable.

In this mode, Quortex I/O will initiate the connection to your SRT servers. In the case where these servers are located behind an enterprise firewall, you will need to check with your IT so they specifically open the UDP traffic coming from Quortex I/O IP.

This IP is available after the wizard, when clicking on the input details.

More questions?

Do not hesitate to reach out to us at to get more information on this topic!

Updated on: 01/03/2024

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