Spotty telnyx trunk performance – possibly misconfiguration, but where?

Hi guys,

Hoping if someone with telnyx trunk experience could guide me on trunk config and ports.

Btw, their support is quite useless and just script readers from India. I’m trialing their service to work as 2nd DID for my business.

So, the issue being that at random time of the day it may work ok for inbound, different time it will not communicate with PBX. Outbound calls seem to be working ok. Also Asterisk debug utility doesn’t even registering inbound call!

I have voip.ms as my main trunk with different DID.

Here is confusion part – ports, what ports do I open with them and effectively what is a good practice regarding them when it comes 2 SIP providers with separate trunks?

Currently my firewall rules look like this:

I’m using SIP port for both providers, I told firewall to only accept traffic from their IP’s but I suspect for telnyx I might put not all their IP’s? Their site is not clear.

Also, their support told me that my trunk config on their site looks ok.

Attached my pjsip trunk config too.


Thank you!!!

For those who may stumble upon similar issues in the future. I found a solution that worked.
I reduced trunk expiration time to 120 s. Apparently their servers couldn’t reregister connection that’s why it was intermittent.

If your IP address is static, I recommend configuring Telnyx with IP authentication and not using registration at all, which eliminates the possibility of ‘lost’ registration, and is also somewhat more secure.

I believe that


is accurate.
Also, the firewall entry for ports 16384-32768 should not be needed, as you have already covered all of Asterisk’s RTP ports with the 10000-20000 entry.

Yep, I removed them and I found a place in PBX that shows actual rtp port range. I also added all their subnets in my firewall, so according the support, they periodically add Ips for media delivery and increase resilience to attack/outage.
No more script kiddies bashing my box so I can sleep better haha.

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