we have a 240 and srx100 configured with site-to-site as per book.
no restrictions between the lans, no NAT.
voip server is on lan on 240-side., voip-phones get IP by dhcp on srx100.
we've been receiving messages about unstable voip-phones.
they restart couple of times per week, sometimes in conversations.
I have now enabled sip-alg on srx100 and called voip-phone on other side, no calls showed on srx100.
Do we need to enable NAT for it to work?
We have similar setup on other site and everything works fine there, no problems with phones.
when pinging other srx100 side of vpn the ping response is around 40, it sometime jumps to 400 and more.
is there a way to troubleshoot stability of vpn?
The configuration and optimization will be different depending on whether your voip system is SIP or H 323 based. There are separate chapters in the ALG configuration guide for each to setup and troubleshoot the connnections.