start of article on a/v support

content/instant-messaging/server-support-for-audio-video-calls.md

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+Title: Prosody server support for A/V calls with Conversations 
+Date: 2020-05-04
+Tags: xmpp, chat, coturn, instant messaging, prosody, audio/video calls
+Slug: server-support-for-audio-video-calls
+Summary: Configure support for audio/video calls with Prosody,
+Category: instant messaging
+Status: draft
+
+[TOC]
+
+Introduction
+---
+
+This is a guide to set up server-side support for audio/video calls over XMPP. To do this we will install and configure `coturn`, a libre STUN/TURN server that helps establish peer connections across firewalls for media streams such as calls. Additionally we will configure `prosody` to talk to `coturn`.
+
+Like the other guides, this one assumes Debian stable running on the server, the fact that you will end up hosting a few of your friends and that you have some basic skills working on a linux command line.
+
+Furthermore it assumes you have already installed and configured Prosody, if you haven't have a look [at how to do so as well!]({filename}instant-messaging/configuring_an_xmpp_server_prosody_0.11.md)
+
+
+Set up firewall 
+----
+
+To make your server communicate make sure following ports are open in your firewall for UDP traffic:
+
+    :::console
+    3478 (TURN)
+    5349 (TURN + TLS)
+	49152-65535 (UDP endpoints for clients)
+
+Set up coturn
+---
+
+First install `coturn`
+
+	:::console
+	sudo apt-get update && sudo apt-get install coturn
+
+