VOIP - Moments of Silence in conversations. (Is this the Solution?)

[cyber7]

Good day everyone
I hope I can get some more insight on this issue. I installed voip phones on my internal lan and am having some issues. All of my conversations keeps giving me dead-space silence where the remote voice gets cut off. Then the conversation will continue...

After going through SIPROXD, VOIP SHAPING, GATEWAY REDIRECTION and going as far as adding a new line, I discovered by chance (https://forum.netgate.com/topic/101184/voip-issues/8) that changing the values in System/Advanced/Firewall&NAT/State Timeouts (seconds - blank for default):

• UDP First = 3600
• UDP Single = 3600
• UDP Multiple = 3600

the problem went away!
My question: Is this the correct approach? Why did the problem go away with these setting and if this is the correct approach, why is it not documented?

kind regards
cyber7 (aka Aubrey Kloppers, Cape Town, South Africa)

[kiokoman]

it is documented
https://docs.netgate.com/pfsense/en/latest/nat/configuring-nat-for-voip-phones.html
they say to set Firewall Optimization Options to Conservative (increase state timeout)

[stephenw10]

Yes, for most that is not required but if the keep alive packet spacing is too high you may need to set conservative mode. Or use custom timeouts as you did.

Steve