DHCP Relay Listening on ALL Interfaces!



  • Hi,

    I have a DHCP server in my local network (192.168.1.10/24) and multiple LAN interfaces on my pfSense (192.168.1.254) box (WiFi, DMZ, GUESTS and so on).

    So I configured pfSense to be a DHCP relay for my DHCP server for all interfaces where the DHCP is not directly attached to.

    This works fine so far- all clients arer getting IP addresses from the DHCP server through the pfSense.

    But the pfSense is listening on the local interface, too! So for every client which requests an address the DHCP server sees two queries:

    Feb 21 07:04:26 praxis dhcpd[8092]: DHCPDISCOVER from 54:04:a6:a4:73:de via eth0
    Feb 21 07:04:26 praxis dhcpd[8092]: DHCPOFFER on 192.168.1.52 to 54:04:a6:a4:73:de via eth0
    Feb 21 07:04:26 praxis dhcpd[8092]: DHCPDISCOVER from 54:04:a6:a4:73:de via 192.168.1.254
    Feb 21 07:04:26 praxis dhcpd[8092]: DHCPOFFER on 192.168.1.52 to 54:04:a6:a4:73:de via 192.168.1.254
    Feb 21 07:04:27 praxis dhcpd[8092]: DHCPREQUEST for 192.168.1.52 (192.168.1.10) from 54:04:a6:a4:73:de via eth0
    Feb 21 07:04:27 praxis dhcpd[8092]: DHCPACK on 192.168.1.52 to 54:04:a6:a4:73:de via eth0
    Feb 21 07:04:27 praxis dhcpd[8092]: DHCPREQUEST for 192.168.1.52 (192.168.1.10) from 54:04:a6:a4:73:de via 192.168.1.254
    Feb 21 07:04:27 praxis dhcpd[8092]: DHCPACK on 192.168.1.52 to 54:04:a6:a4:73:de via 192.168.1.254
    Feb 21 07:06:50 praxis dhcpd[8092]: DHCPINFORM from 192.168.1.52 via eth0
    Feb 21 07:06:50 praxis dhcpd[8092]: DHCPACK to 192.168.1.52 (54:04:a6:a4:73:de) via eth0
    Feb 21 07:06:50 praxis dhcpd[8092]: DHCPINFORM from 192.168.1.52 via 192.168.1.254
    Feb 21 07:06:50 praxis dhcpd[8092]: DHCPACK to 192.168.1.52 (54:04:a6:a4:73:de) via eth0
    

    You see every sequence is doubled so the client is busy in requesting it's IP address through relay as well directly. This is crappy and I have some older clients which can not deal with it.

    So how can I prevent dhcp relay to listen on LAN interface? According to configuration it shouldn't!
    dhcp.png

    /KNEBB



  • Hi,

    I had the suspection it might have to do with VLANs as the interfaces where the relay should listen to are configred as VLANs on physical interface.

    Changed this meanwhile but still the same!

    So for sure DHCP-Relay listens on interfaces where it should not to!

    Is there anywhere a bugtracker where I can enter a bug?

    /KNEBB



  • Found it on my own.

    Entered it there.


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