SRX – “VPN monitoring” causes IPSec to bounce
Just making a note here because this will probably trip me up again in the future: I have a customer with a VPN running from an SRX650 on 11.4R9.4 to a variety of other devices. One of these is some kind of Huawei device, and the other a Vyatta router. I’ve no idea what versions or models these are because they’re not under the customer’s control.
I noticed that these two VPNs didn’t appear to be staying up. You could tell because of the lifetime of the IPSec security association. It is set in the configuration to 1800 seconds and counts down – when it gets near zero, the SA is re-negotiated. In this case however, the SA never dropped much below 1400 seconds remaining before being renegotiated.
You can see this by issuing the command “show security ipsec sa” and looking at the fourth column to see the lifetime remaining. If you specify the index number you get more detail as can be seen below:
user@LON-SRX650> show security ipsec sa index 12
ID: 12 Virtual-system: root, VPN Name: VPN-1
Local Gateway: x.x.x.x, Remote Gateway: y.y.y. Continue reading