First outbound call after a while take around 15-18 second to ring

[ECOM GROUP (Mauritius)]

Hello,

Issue on outgoing calls,
First outgoing call i dial after 5-10 minutes of idle, it take around 15-18 second to hear the first ringing tone.

i hang up and dial again instantly, it then ring quick as normal.

issue happen every 5 - 10min i try to make a call.

Using a SIP Trunk with a Local Private IP, connected to a Local Debian mini pc which is on same network of the SIP Trunk eSBC LBB240.

some error i have seen in the log is Call or Registration to 8xxxxx@(Ln.10004@Line4xxxx) has failed. 0.0.0.0 replied: 503 Transport failure: no transports left to try; warning: No other DNS entries to try (7,111); internal .

Issue happen on all Phone, IP Phone, Mobile App , Locally provisioned and mobile app via tunnel.
Call extension to extension seem fine.
Can someone advise?

DNS server of my Debian is 8.8.8.8 8.8.4.4
Static IP

 

[Alphabetic]

Is it the same when dialling EXT to EXT or when dialling via trunk only?

 

[ECOM GROUP (Mauritius)]

Is it the same when dialling EXT to EXT or when dialling via trunk only?

Via trunk only. I just noticed something with length of numbers dialed. testing and will update it here

 

[StefanW]

I think that some of your DNS servers (entered into the host where the PBX resides on) do not resolve and it needs a timeout to go to the next configured dns server. Once we have a DNS result it will be cached for the TTL. On expiry, it will take then again sometime...

 

[ECOM GROUP (Mauritius)]

I think that some of your DNS servers (entered into the host where the PBX resides on) do not resolve and it needs a timeout to go to the next configured dns server. Once we have a DNS result it will be cached for the TTL. On expiry, it will take then again sometime...

@StefanW thanks for your response, How can i fix it in this case?
My Internet have Dynamic IP
And have a DNS,

My Debian Machine have an static Private IP but with google DNS 8.8.8.8 8.8.4.4 instead of ISP Dns..

 

[StefanW]

can you post your full resolve.conf from the host plz

 

[ECOM GROUP (Mauritius)]

can you post your full resolve.conf from the host plz

@StefanW here is inside the resolv.conf below. that's all

nameserver 8.8.8.8
nameserver 8.8.4.4

 

[ECOM GROUP (Mauritius)]

can you post your full resolve.conf from the host plz

Can i share the wireshark capture here?

 

[Alphabetic]

Does your firewall check pass and are you able to unregister/register your SIP trunk?

I would screenshot your wireshark and omit sensitive information.

 

[ECOM GROUP (Mauritius)]

Does your firewall check pass and are you able to unregister/register your SIP trunk?

I would screenshot your wireshark and omit sensitive information.

Yes its all green. SIP Trunk is IP Based, a Private IP from my eSBC

 

[cobaltit]

If your SIP trunk is local (eSBC on the same LAN/subnet as 3CX) and you have an IP in the trunk settings it's not a DNS issue. I would confirm auto-discovery is turned off to make sure it's not trying to do something it shouldn't be.

 

[ECOM GROUP (Mauritius)]

If your SIP trunk is local (eSBC on the same LAN/subnet as 3CX) and you have an IP in the trunk settings it's not a DNS issue. I would confirm auto-discovery is turned off to make sure it's not trying to do something it shouldn't be.

Yes correct, Trunk is not on auto discovery, it was and i have removed it to see, but still same.

 

[cobaltit]

So one of two possibilities here. Either there is some sort of NAT between 3CX and your eSBC (unlikely) or the delay is from the eSBC. IP authenticated should just go. Just to confirm is this a single interface on your 3CX box?

 

[ECOM GROUP (Mauritius)]

eSBC is a box,
3CX is on a Debian Mini pc. ( since someone have having same issue as you just seen, he is using on premise 3CX Mini PC as well. Do you think it is an issue with the network card of the Mini PC? Realtek.

there is no issue on the eSBC side as far as i know.
Nat issue , its currently using full cone nat. and i will try to disable the firewall and see.

 

[ECOM GROUP (Mauritius)]

So one of two possibilities here. Either there is some sort of NAT between 3CX and your eSBC (unlikely) or the delay is from the eSBC. IP authenticated should just go. Just to confirm is this a single interface on your 3CX box?

I have PM you a Wireshark capture so that you can better understand my issue.

 

[Steele Burgess]

Hello,

Issue on outgoing calls,
First outgoing call i dial after 5-10 minutes of idle, it take around 15-18 second to hear the first ringing tone.

i hang up and dial again instantly, it then ring quick as normal.

issue happen every 5 - 10min i try to make a call.

Using a SIP Trunk with a Local Private IP, connected to a Local Debian mini pc which is on same network of the SIP Trunk eSBC LBB240.

some error i have seen in the log is Call or Registration to 8xxxxx@(Ln.10004@Line4xxxx) has failed. 0.0.0.0 replied: 503 Transport failure: no transports left to try; warning: No other DNS entries to try (7,111); internal .

Issue happen on all Phone, IP Phone, Mobile App , Locally provisioned and mobile app via tunnel.
Call extension to extension seem fine.
Can someone advise?

DNS server of my Debian is 8.8.8.8 8.8.4.4
Static IP

Try this. Hard code the sip trunk ip address in Registrar/Server/Gateway Hostname or IP. Then hard code the trunks ip in the Outbound Proxy section also. This solved a lot of issues for me on outgoing calls when I had issues and nobody seemed to have an answer for me. Let me know if this resolves your issues. Granted I'm on a Windows machine so take that into consideration also.

 

[ECOM GROUP (Mauritius)]

Try this. Hard code the sip trunk ip address in Registrar/Server/Gateway Hostname or IP. Then hard code the trunks ip in the Outbound Proxy section also. This solved a lot of issues for me on outgoing calls when I had issues and nobody seemed to have an answer for me. Let me know if this resolves your issues. Granted I'm on a Windows machine so take that into consideration also.

Thanks, can you explain how to hard code it?

 

[Steele Burgess]

Just use the static ip of the trunk in both areas. Not the dns name. I've attached a screenshot.

 

[ECOM GROUP (Mauritius)]

Just use the static ip of the trunk in both areas. Not the dns name. I've attached a screenshot.

Ah ok, Done that already yesterday, Issue still here.

 

[Steele Burgess]

Then it's not a dns issue. I usually would try another trunk provider also when I'm troubleshooting.