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new subnet needed on SRX220H2

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  • 1.  new subnet needed on SRX220H2

    Posted 05-30-2017 07:08

    Hi there,


    I need to set up a new subnet because I am being out of IP address.


    Now we use 10.196.24.X network with subnet mask, gateway

    I need to set up a new range like this: 10.196.25.X but pointing to the same gateway (


    I want to activate the DHCP pool from ~


    How can I do that? I am very new on Juniper devices.If possible please tell me how to do that using the J-web interface, if not possible, please send me the commands.


    I have a SRX220H2 with JUNOS Software Release 12.1X44-D15.5.

  • 2.  RE: new subnet needed on SRX220H2

    Posted 06-01-2017 06:52

    In long term most proper way is to change your existing /24 subnet to /23 ( Thus your new IP range will be -


    Only downside you have to consider - that subnet should be adjusted for existing x.x.24.x hosts.




    dhcp server setup:

  • 3.  RE: new subnet needed on SRX220H2
    Best Answer

    Posted 06-02-2017 02:51

    As Algarz notes, if you want the SAME gateway for the additional addresses then you must expand the netmask and then add an additional pool to the dhcp range.


    Another option is to add a secondary ip address with the new subnet gateway to the same interface.  Then create a new dhcp setup for that range.  This will work but does put the broadcast domain for two diferent subnets into the same vlan which would be considered non-standard.


    Another option is to add a new vlan for this subnet.  This can be done by using another port or by adding a vlan tag to an existing port down to your switches.  Changes would be needed on both the switches and SRX for this and would depend on if you are using a dedicated port or trunk port for the setup.


    If you let us know which version you want to pursue, post your current configuration for the interfaces and dhcp and we can asist with making the changes needed.

  • 4.  RE: new subnet needed on SRX220H2

    Posted 06-02-2017 15:15

    Putting subnet as a secondary is the easiest path to go. But you won't be able to satisfy your "..pointing to the same gateway .." requirement.

    And also you might face a bunch of limitations secondary subnet causes. As a prime example - you will have problems in case you will want to issue dhcp addresses on both subnets simultaneously.