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Bug #9466

closed

DHCP (IPv4) relay mistakenly listening on upstream interface

Added by Foster Snowhill almost 5 years ago. Updated over 4 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
Category:
DHCP Relay
Target version:
Start date:
04/10/2019
Due date:
% Done:

100%

Estimated time:
Plus Target Version:
Release Notes:
Affected Version:
All
Affected Architecture:

Description

Hello!

Not sure if this is dhcrelay's intended behaviour, but it is listening on the upstream interface when it's not asked to, and thus duplicates packets coming from inside the upstream network.

My interfaces:

  • LAN_TN = lan = vmx0 (192.168.2.1/24)
  • LAN_UN = opt3 = vmx0.10 (192.168.3.1/24)
  • LAN_Docker = opt7 = vmx0.20 (192.168.6.1/24)

DHCP relay is configured as shown in the attached relay_config.png. Config.xml looks like this:

<dhcrelay>
    <interface>opt7,opt3</interface>
    <server>192.168.2.8</server>
    <agentoption></agentoption>
    <enable></enable>
</dhcrelay>

However it starts up listening on the upstream as well:

/usr/local/sbin/dhcrelay -i vmx0.20 -i vmx0.10 -i vmx0 -a -m replace 192.168.2.8

which causes it to catch the broadcast packets on the upstream network and duplicate those requests, as seen on packets.png. pfSense 2.4.4-p2 running on amd64, ESXi VM.

Not critical im my setup, but might be problematic for those whose upstream DHCP server is located on the WAN, for example.


Files

packets.png (15.7 KB) packets.png Duplicated packets as seen from the client Foster Snowhill, 04/10/2019 08:54 AM
relay_config.png (30.4 KB) relay_config.png DHCP relay configuration in web UI Foster Snowhill, 04/10/2019 08:54 AM
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