[Devel] Natping and router LinkSys wrt54gc problem

[Piotr Szymanek]

Hello

I have problem with router LinkSys wrt54gc
I trying use MS RTC client and openser server with NatHelper
in config I set
modparam("registrar", "nat_flag", 6)
modparam("nathelper", "natping_interval", 30) # Ping interval 30 s
modparam("nathelper", "ping_nated_only", 1)   # Ping only clients behind NAT

Openser seems to work properly becouse
using Ethereal on my client behind NAT I see incoming small udp frames to 
me.
Unfortunly even than external mapped  port freezes after about 5 minutes and 
nobody can't call to me.
If I send invite, that mapped port back to alive for next 5 minutes.

How to resolve this problem ?
I don't want to reregister or call to somebody every 5 minutes to voip work 
fine all time :(

Thanks
Piter