In Junos 15.1X49-D70, the default behavior of the IPv6 forwarding mode is changed from ' drop' to ' flow based' on the following SRX models:
In Junos 9.6 or later (but before 15.1X49-D70 ), the default IPv6 forwarding mode is ' drop .'
root@vsrx> show security flow status Flow forwarding mode: Inet forwarding mode: flow based Inet6 forwarding mode: drop <--- MPLS forwarding mode: drop ISO forwarding mode: drop Flow trace status Flow tracing status: off Flow session distribution Distribution mode: RR-based GTP-U distribution: Disabled Flow ipsec performance acceleration: off Flow packet ordering Ordering mode: Hardware
In order to enable the use of IPv6 and change the forwarding mode to " flow based " the following command is used, followed by a reboot. Refer to KB25697- How to enable the IPv6 flow (or packet) mode on SRX [juniper.net]
set security forwarding-options family inet6 mode flow-based
However, starting with Junps 15.1X49-D70 , IPv6 forwarding mode is set to " flow based " , by default. It can be checked using the command " show security flow status " .
root@vsrx> show security flow status Flow forwarding mode: Inet forwarding mode: flow based Inet6 forwarding mode: flow based <--- MPLS forwarding mode: drop ISO forwarding mode: drop Flow trace status Flow tracing status: off Flow session distribution Distribution mode: RR-based GTP-U distribution: Disabled Flow ipsec performance acceleration: off Flow packet ordering Ordering mode: Hardware
In order to disable IPv6 and change the forwarding mode to " drop " use the following command:
set security forwarding-options family inet6 mode drop
This change in default behavior also enables the device to work without any requirement of a reboot when switching between the different flow modes for IPv6, namely packet based, flow based, and drop .
For IPv4, the default mode on SRX1500, SRX 4100/4200, SRX 5400/5600/5800, and vSRX will remain as " flow based ". A reboot is not required to change between the different flow modes for IPv4 namely, packet based, flow based and drop .
Note: Packet based is NOT supported on SRX5000 devices.
The SRX3000 Series devices maintain existing behavior for IPv4 (default mode: flow based ) and for IPv6 (default mode: drop ), due to memory constraints. Also, a reboot will be required to change between the different flow modes ( flow based/drop ) for IPv4 and/or IPv6 on the SRX3k Series devices.