SRX Services Gateway
SRX Services Gateway

DHCP always an issue for me on Juniper srx240

‎10-12-2019 08:20 AM

I have posted multiple times about DHCP lease time on my juniper srx240 router

here is my configuration for DHCP lease time


dhcp {
pool {
address-range low high;
maximum-lease-time 6048000;
default-lease-time 6048000;
router {;

but yet when the router restarts, most of the hosts lose their ip address

i am unable to set statis ip and yet DHCP refuse to respect lease time i gave to allow hosts to keep their ips for a very long time


can someone please tell me what am not doing right or if juniper srx240 router is just useless with DHCP?

it is useless if a router can not respect DHCP lease time as it is disastrous everytime a restart happens as i have to remap all ips all over again.


so annoying and it is with anger i am typing this

SRX Services Gateway

Re: DHCP always an issue for me on Juniper srx240

[ Edited ]
‎10-13-2019 03:18 PM

Hi, im just going to speak my mind so don't take it personally.


There are a number of red flags in your post.....


1) There is no reason to create a 70-day lease time.

2) There is no reason to build a 65534-host capable dhcp server on one network with a SRX240.

3) If either 1 or 2 is needed you have a design issue.


With that out of the way; Possible fixes/issue;


1) Make sure you are running the JTAC release version for the SRX240 - 12.1X46-D86 or 12.3X48-D85 as per Junos Versions

2) There was a problem report about DHCP leases being dropped during a reboot which might be the same for you, hence version ugrade suggestion. The issue applies to the new way of configuring DHCP but that does not mean old DHCP is not affected as well. DHCP PR1050723 

3) If you need long leases, why not reserve them in DHCP?

# set system services dhcp static-binding 00:AB:CD:11:EF:GH fixed-address

4) If you don't want to do that and your configuration has a gazillion addresses, you can also use:


# set system services dhcp pool maximum-lease-time infinite

5) View the address bindings (In CLI), reboot the SRX or restart DHCP and look at the leases again. Determine of the client are being assigned different addresses than before. If so, I would say you have the same issue as the problem report in 2)


> show dhcp server binding detail

Restarting DHCP:

> restart dhcp-service gracefully


Juniper/Microsoft/Citrix Engineer at IT Live Ltd, Auckland, New Zealand.
SRX Services Gateway

Re: DHCP always an issue for me on Juniper srx240

‎10-13-2019 05:27 PM

Sounds like a better solution for you would be to configure static dhcp bindings on the SRX.  This will associate the same dhcp delivered address to the device and only to that device.  This allows the devices to be dhcp but the address to be consistent across reboots.  It works by associating the device mac address with the desired ip address in the configuration.


Steve Puluka BSEET - Juniper Ambassador
IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP)