Is “broadcast-address” necessary in dhcpd.conf

This is an old question, but:

You need to compile dhcpd with USE_SOCKETS. If you don't, it uses some pcap code to receive packets, and that pcap code has hard-coded assumptions that the link layer is Ethernet, so doesn't work on tunnel interfaces.

Now that I've found out something about dhclient options, I took a look at /etc/sysconfig/network-scripts/ifup-eth. In the very worst case, you can edit that script to run dhclient with the -s option to specify the DHCP server.

There's also an optional /etc/dhclient.conf file, but looking at man dhclient.conf I don't see any option that corresponds to the "-s" command line switch.