SRX: Facing issues with unlimited lease time configuration for DHCP

If lease time for DHCP is set to “unlimited”, it may cause DHCP client to crash.

On SRX Series devices, DHCP service might crash when it receives a DHCP offer containing a large lease value.
This issue affects all SRX platforms and might occur if following conditions are met:
*Configure an interface as a DHCP client on the SRX device
*SRX receives DHCP offer messages containing a large lease value (e.g. the lease value is greater than or equal to 230000000 seconds)
DHCP service crashes when it receives a DHCP offer containing a large lease value; persistently receiving this kind of DHCP offer will cause the DHCP service thrashing and not restarted. There is no coredump file generated. And the below log shows in messages log:
init: dhcp is thrashing, not restarted

Executing the command “show system services dhcp client” will show the dhcp subsystem stopped:
user@srx> show system services dhcp client
error: the dhcp subsystem is not running

Note: Configuring both dhcpd and jdhcpd together is not allowed.
1) Configure the lease value to a short time that is less than 230000000 seconds on the DHCP server.
2) If the SRX device runs on 12.1X44-D10 or later releases, configure JDHCPD client instead of DHCP client on the DHCP client to solve the issue.
Refer example below:


About the author

James Palmer

Leave a Comment