Interface secondary ip problem



  • hi every body
    i have one LAN interface that necessary to asign 2 ip range . first and primary range is 192.168.1.1/24 and secondary range is 172.16.15.1/24. also i configured DHCP server on this LAN interface . DHCP range is 192.168.1.100-200.(first range)
    at first i assigned first range and then i add IP Alias with second range . up to this state there is no problem and clients get ip address within mentioned range.
    but when every time server restarts, DHCP try to give ip to client with second range (172.16.15.0/24) and ignore the first range also no clients can get ip address and in log says: no ip to get to leases…
    how can i solve this problem ??



  • Not enough information. For instance, your DHCP server would not try giving out a 172.16.15.x address unless it was configured to do so but you don't state this. Also, if you're trying to run DHCP instances on two LANs running across one NIC, you're going to have to have configured VLANs on your switch and your firewall.

    Might be worth posting shots of your network interface configurations (for both LANs), as well as your DHCP configs for each network.



  • thank u , the strange thing is exact you have mentioned. I configure DHCP on the LAN interface to use the first range( 192.168.1.100-200) but it tries to use range from second range instead ofcourse after restarting server.
    you  consider these steps : 1- I asign first ip range(192.168.1.1/24) on LAN interface ***2- config and start DHCP server on LAN interface with ip pool= 192.168.1.100 - 200    **** 3-asign ip range 172.16.15.1/24 as Alias on LAN interface .
    after these 3 steps every thing work fine but problem occurs when pfsense reboots. after rebooting DHCP server try to use alias ip range as pool but it cant so it gives error to clients!
    you thing steel I should use vlans?/
    how can i do vlans on this physical interface ??
    thank u


  • LAYER 8 Netgate

    You cannot do what you are trying to do.

    Putting two different subnets on the same segment is bad design in IPv4.

    How is the DHCP server supposed to know which subnet a DHCPREQUEST broadcast is for? It sounds like the DHCP config might be getting confused but if you design your network properly it works fine.

    If you want to use the same physical interface for two different networks you have to use VLANs which will give you 1 or more logical/virtual interfaces on the same physical interface. There is more to VLANs than adding IP aliases. You might want to search the internet for VLAN and/or 802.1q.



  • @hamedice:

    you thing steel I should use vlans?/
    how can i do vlans on this physical interface ??

    Try using Google - it's this really useful thing the Internet has which allows you to search for information on topics you need to know. For instance, I typed 'pfsense vlans' into it and came up with this:

    https://www.iceflatline.com/2013/09/how-to-create-and-configure-vlans-in-pfsense/

    As Derelict says, you will not be able to run two DHCP instances on one physical interface unless you set the respective VLANs on the NIC. You will also need to create or modify your settings on your switch to match the VLAN IDs you set up on the firewall. I'll leave you to Google that for yourself.



  • than you both very much


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