[ipxe-devel] Proxy DHCP server reply port

Gene Cumm gene.cumm at gmail.com
Mon Jun 2 11:05:24 UTC 2014

On Mon, Jun 2, 2014 at 5:42 AM, Wissam Shoukair <wissams at mellanox.com> wrote:
> Hi,

> When we send ProxyDHCP Request to port 4011 (PXE_PORT), the ProxyDHCP ACK
> that we get in response it’s from port 67 (BOOTPS_PORT), and we see that in
> iPXE stack drops this packet because the server’s port is not 4011.
> I don’t think that the server’s port which the packet came from should be
> only 4011 (PXE_PORT).

If I send a ProxyDHCP request to udp/4011, I'd expect the server to
respond on udp/4011.  If I send a DHCP request to udp/67, I'd expect
the server to respond on udp/67.  Unless responses are expected from
arbitrary udp ports, most protocols will ignore that kind of response
and most packet filter systems will drop those packets.  Protocols
that change ports are at least well documented and often will perform
a handshake before moving to another port.

> Any suggestions ?

Specifying the ProxyDHCP system that's generating this response.  To
me, this sounds like some DHCP daemon that's listening on both 67 and
4011 and is unfortunately defaulting to 67.


More information about the ipxe-devel mailing list