Netgate Discussion Forum
    • Categories
    • Recent
    • Tags
    • Popular
    • Users
    • Search
    • Register
    • Login

    Duplicate relayed unicast DHCP requests

    Scheduled Pinned Locked Moved DHCP and DNS
    1 Posts 1 Posters 763 Views
    Loading More Posts
    • Oldest to Newest
    • Newest to Oldest
    • Most Votes
    Reply
    • Reply as topic
    Log in to reply
    This topic has been deleted. Only users with topic management privileges can see it.
    • N
      norispfsense
      last edited by

      Hello all. I experience a similar problem like in https://forum.pfsense.org/index.php?topic=19959.msg102605. I have updated to the 2.3.2 respectively the 2.3.2_1 release and I observe unicast DHCP requests being forwarded on interfaces for which the dhcrelay was configured.

      Example:
      09:20:43.083455 IP xxx.xxx.67.81.68 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:43.083638 IP xxx.xxx.25.1.67 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:43.083644 IP xxx.xxx.25.5.67 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:43.083719 IP xxx.xxx.25.1.67 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:43.083801 IP xxx.xxx.25.4.67 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:52.006764 IP xxx.xxx.67.81.68 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:52.006840 IP xxx.xxx.25.4.67 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:52.006914 IP xxx.xxx.25.1.67 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:52.006955 IP xxx.xxx.25.5.67 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:52.007067 IP xxx.xxx.25.1.67 > xxx.xxx.25.6.67: BOOTP/DHCP, Request from 00:xx:xx:xx:xx:e3, length 300
      09:20:58.093810 IP xxx.xxx.25.6.67 > xxx.xxx.67.81.68: BOOTP/DHCP, Reply, length 338
      09:20:58.099044 IP xxx.xxx.25.6.67 > xxx.xxx.67.81.68: BOOTP/DHCP, Reply, length 338

      Our DHCP server gets spammed with log entries due to the duplicated DHCP requests. I am curious as there are ways to mitigate or to eliminate that behaviour. What I already did was to add the option "-c 1" to the dhcrelay so that the number of duplicated unicast DHCP requests is reduced.

      1 Reply Last reply Reply Quote 0
      • First post
        Last post
      Copyright 2025 Rubicon Communications LLC (Netgate). All rights reserved.