[ATP/FLEX] What does the log message 'Packet (ESP) cannot be sent. Reason: System dropped' mean?

Zyxel_Jeff

Question :

What does the log message 'Packet (ESP) cannot be sent. Reason: System dropped' mean?

Answer :

The error message "Packet (ESP) cannot be sent. Reason: System dropped" is triggered by the VPN log outprint function, an internal kernel function that failed to process the packet correctly.

This issue may be caused by:

1.Routing issues:

Routing table query failure
ARP resolution failure
Send queue is full

2. Packet content problems:

Packet size exceeds MTU
Packet format error
Checksum error

Those issues will not impact the VPN service. For instance, if the ACK packet is not received from the destination IP, the LAN PC will automatically reinitiate the VPN tunnel. Therefore, users can safely ignore these log messages.