# RTP UDP port negotiation - expected behavior

**URL:** <https://community.wowza.com/t/rtp-udp-port-negotiation-expected-behavior/40679>\
**Category:** Wowza Streaming Engine\
**Tags:** server-administration\
**Created:** [October 23, 2013, 12:44pm UTC](https://community.wowza.com/t/rtp-udp-port-negotiation-expected-behavior/40679 "2013-10-23T12:44:04Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Robert\_Engelmann](https://avatars.discourse-cdn.com/v4/letter/r/e9bcb4/32.png) [@Robert\_Engelmann](https://community.wowza.com/u/Robert_Engelmann)\
**Post date:** [October 23, 2013, 12:44pm UTC](https://community.wowza.com/t/rtp-udp-port-negotiation-expected-behavior/40679/1 "2013-10-23T12:44:04Z")

</div>

Wowza Media Server 3 Perpetual Edition 3.6.2.17 build7663

What is the expected behavior of the UDP ports negotiated by RTSP?

We are sending live streams to Wowza from mobile devices via RTSP/UDP and have noticed the server giving out pairs of ports for each SETUP but continuing on to 10000-10001 once it reaches what I thought was the upper limit of 9999.

Should the server cycle back to the beginning of what is in DatagramStartingPort or continue past 9999 as we are observing?

```auto
<DatagramStartingPort>6970</DatagramStartingPort>

```

In our case we changed it to 9992

```auto
<DatagramStartingPort>9992</DatagramStartingPort>

```

Here is the response we got after sending the SETUP:

```auto
RTSP/1.0 200 OK
Date: Wed, 23 Oct 2013 12:20:52 PDT
Transport: RTP/AVP/UDP;unicast;client_port=5000-5001;mode=receive;source=0.0.0.0;server_port=10000-10001
Session: 1254165248;timeout=60
Expires: Wed, 23 Oct 2013 12:20:52 PDT
Cseq: 4
Server: Wowza Media Server 3.6.2.17 build7739
Cache-Control: no-cache

```

We need to understand the behavior in order to open our firewall to the correct range. Currently it’s open from UDP 9992 to 9999 only.

Thanks,

Robert

---

<div class="post-metadata">

**Author:** ![Tim\_Dougherty](https://sea2.discourse-cdn.com/flex002/user_avatar/community.wowza.com/tim_dougherty/32/596_2.png) [@Tim\_Dougherty](https://community.wowza.com/u/Tim_Dougherty)\
**Post date:** [October 23, 2013, 1:59pm UTC](https://community.wowza.com/t/rtp-udp-port-negotiation-expected-behavior/40679/2 "2013-10-23T13:59:20Z")

</div>

This issue has been submitted in ticket #70684.

-Tim