dynamic configuration of wired network interfaces looks quite broken

[Richard Ryniker]

The most simple (and perhaps too obvious) explanation would be your DHCP
server is not configured to respond to requests from the wired network
interace, but responds appropriately to requests from the wireless
network interface.  It this used to work, perhaps something changed your
DHCP server's configuration file (or the location of the configuration
file).  Check to verify whether the log file on the server host shows
receipt of the wireless network request, but no receipt of the wired
network request.

I use iptables to limit local network activity, and find it useful on
occasion to replace my regular rules by a completely permissive
configuration to test whether some error or unexpected rule consequence
has interfered with my desired network behavior.  If a failing application
works with the relaxed rules, I know to examine my usual rule set to
learn why it prevented delivery of a desired message.

>From your description, it does not appear likely to be your problem, but
on more than one occasion I found DHCP servers unexpectedly active on two
or more of my hosts.  This is a wonderful formula for confusion and
embarassment: no amount of scrutiny of a correct configuration file will
explain incorrect results delivered by a different server.  I sometimes
want multiple DHCP servers, but configuration to limit them to disjoint
sets of clients or networks is more difficult than with only one server.