DHCP-Relay duplicating unicast packets

Marc Haber mh+dhcp-users at zugschlus.de
Fri Sep 11 14:55:11 UTC 2015

On Fri, Sep 11, 2015 at 09:09:21AM -0400, Ray Soucy wrote:
> You could be seeing this if you're using the native (untagged)
> interface in addition to VLAN sub-interfaces:
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=643564

This bug is the reason why I updated my DHCP packages to 4.3.2.

> Also note that the default behavior of dhcrelay is to relay relay
> packets [sic], you may want to disable this using the "-m discard"
> option.

The issue is, why is the DHCP relay acting on a unicast packet that is
addressed to the DHCP server? In my understanding, it is only supposed
to act on broadcast packets. A unicast packet can (and is!) simply be
routed, no relay needed here.


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