DHCPREQUESTs and What the Logs Show

Bruce Hudson Bruce.Hudson at Dal.Ca
Fri Feb 11 14:52:19 UTC 2011

> Feb 10 15:56:53 dh1 dhcpd: DHCPREQUEST for <ip> from <mac> via bce0

    Without other evidence, I would say that this is a normal DHCP renewal
request. The initial DISCOVER/REQUEST 4-way handshake is broadcast so the
servers sees the request via the relay. When renewing, clients unicast the
requests directly to the server so the GIADDR field is empty and the
server logs the request "via <interface>".
    If the slave server is seeing the same requests via a relay then this
is a different issue altogether. That means client broadcasts are being
dumped onto the master's network; or some broken relay is forwarding DHCP
traffic without setting the GIADDR field. Are requests being duplicated;
once "via bce0" and once via a relay?

    I suggest you sniff traffic on the server to see what is going on.
Bruce A. Hudson				| Bruce.Hudson at Dal.CA
ITS, Networks and Systems		|
Dalhousie University			|
Halifax, Nova Scotia, Canada		| (902) 494-3405

More information about the dhcp-users mailing list