RUTX50 - dropped calls VOIP

[flor62]

VOIP with sipgate does work in general. But sometimes calls drop after 2 minutes. I read otherwise that UDP-Timeout shoud be 300 or more. Where can i cange the UDP-Timeout for VOIP?

[Marija]

Hello,

I have asked our developers if this is possible and will let you know as soon as I receive an answer from them.

Best regards,

[luckman212]

I believe you can view the current (presumably default) values with

# sysctl net.netfilter | grep nf_conntrack_udp

On my RUTX11, that shows

net.netfilter.nf_conntrack_udp_timeout = 60
net.netfilter.nf_conntrack_udp_timeout_stream = 180

You should be able to adjust those with something like (600=5 minutes)

# cat <<EOF >> /etc/sysctl.conf
net.netfilter.nf_conntrack_udp_timeout=600
net.netfilter.nf_conntrack_udp_timeout_stream=1800
EOF

# sysctl -p

I also note there are some default files at

/etc/sysctl.d/10-default.conf
/etc/sysctl.d/11-nf-conntrack.conf

Not sure if these should ever be touched.

[flor62]

Yes, I did the same, but also added:
net.netfilter.nf_flowtable_udp_timeout

I created a new file: /etc/sysctl.d/custom-voip-settings.conf

All three elements are entered there with their values (instead of xxx):
net.netfilter.nf_conntrack_udp_timeout=xxx
net.netfilter.nf_conntrack_udp_timeout_stream=xxx
net.netfilter.nf_flowtable_udp_timeout=xxx

This eliminates the need to manipulate system files. This file automatically overwrites the system defaults.

[Marija]

Hello @flor62,

It’s possible that the issue is caused by the SIP connection tracking helper.
You can try disabling it by navigating to Network → Firewall → Settings, disabling the Automatic helper assignment option, then heading over to Network → Firewall → Zones, editing the LAN zone (assuming that’s where the phone is located), and under Advanced settings, enabling all connection trackers EXCEPT the SIP one:

If this does not resolve the issue, please provide answers to the following questions:

1. You mentioned that

@flor62

But sometimes calls drop after 2 minutes

• Could you please specify how often “sometimes” happens?
• Why do you believe that the UDP timeout is causing it?
• Is it always exactly 2 minutes?

2. What is your network topology?

• It would be helpful if you could provide a diagram with all devices and their IP addresses.

3. Is the SIP server on the LAN or WAN network?
4. Are you using a mobile connection for VoIP communication?
5. Are you using any VPNs?

Best regards,

[flor62]

Hello Marija,

Thank you for your reply. I have deactivated the SIP VOIP Helper in all active zones. I will test it in the next few days and share the results.

Best regards – Rolf