For the traffic to use the vpn connection the source and destination addresses have to be setup as allowed by the VPN configuration.
And the routing on both sides of the tunnel also has to select the tunnel as the destination for that traffic.
Is your VPN a policy based or route based tunnel? And is the flow setup to use this path?
If route based vpn is the return route to the SRX source ip address setup on the other side of the tunnel?
Is the security policy in place to permit the traffic on both sides of the tunnel?
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Steve Puluka BSEET - Juniper Ambassador
IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP - Retired)
http://puluka.com/home------------------------------