Addition of a DPC on a 5450 causing packet loss

wally4 — Mon, 28 Sep 2026 14:13:46 GMT

Hello Everyone,

Hope you all are doing well.

I have a question regarding an issue we experienced after adding a new DPC to a firewall.

After installing a new DPC in Slot 6 and changing the session distribution method to Session Load, the firewall started experiencing connectivity issues with the router and peer IP addresses.

We observed a significant increase in packet loss, from 0% to approximately 25–30%, which eventually caused the IPsec tunnels to go down.

As part of the troubleshooting, we performed the following:

Administratively powered off the DPC in Slot 6.
Rebooted the firewalls.
Monitored connectivity and packet loss after the reboot.

After powering off the DPC and rebooting the firewalls, connectivity returned to normal. The packet loss disappeared, and the IPsec tunnels remained stable.

The DPC installed in Slot 6 was a new card.

Has anyone experienced similar behavior after installing or enabling a new DPC? Could there be an issue with the DPC itself, session distribution after switching to Session Load, or another chassis-related factor that could explain the increased packet loss?

Any suggestions on what logs, counters, or commands would be useful to check if this happens again would also be appreciated.

Best Regards,
Wally

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Addition of a DPC on a 5450 causing packet loss