VOIP help

Hi @Crown_Services_Tech 

In order to understand the FortiGate role in the VOIP flow please help us with the below points:-

-- What is FortiOS version?

--Are you making an inbound call or an outbound call?

--What is the port used for communication?
--What is the protocol used? H323 or SIP
--Where is the location of the PBX?
--Is the communication over VPN or over the Internet?
--Is SDP payload NAT required in your setup?
--How is the RTP flow? Please provide a network diagram with the call flow information.

You can collect the sniffer logs on Fortigate using the below command:-

diag sniffer packet any 'host x.x.x.x' 6 0 l -----where x.x.x.x is the source IP of the phone you are making a call from

Direct pcap file of the sniffer can be collected from the GUI also

https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-Packet-Capture-on-FortiOS-GUI/ta-p/194444

Regards

Priyanka

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Hello @Crown_Services_Tech 

From the above query description, I can understand that, you are facing issues with  Call getting transferred from one person's phone to another.

Thus, to verify the voltage, could you please share of below command:
#di de an voiced ha an

Thanks

Shaleni

Thanks
Shaleni

Have you resolved it?

What type of Voice system are you using?
have you tried setting a traffic shaper and enabled dscp?
Solved: 3CX VoIP issues - Resolved... - Fortinet Community

I had a similar issue a while ago, and what worked was setting the SIP ALG to off and then fine-tuning the policy to allow bidirectional UDP traffic on the right port ranges. I'm using telxi with no VOIP call drops ever since making those changes on my FortiGate. Also double-check that your NAT isn't hiccuping on re-INVITE requests.

This sounds like a multi-site VoIP design issue rather than just a firewall fault. When offices are merged, SIP signalling delays and NAT handling problems can cause calls to keep ringing after pickup, jump between phones and drop audio, especially during peak traffic hours, which points to bandwidth or QoS contention. You can check basics like disabling SIP ALG and prioritising voice traffic on the FortiGate, but the cleaner fix is moving to a cloud phone system  where each phone registers directly to the cloud instead of relying on site-to-site VoIP, eliminating these issues. For more information, you can visit: https://www.techomsystems.com.au/cloud-phone-system