we're using the isc-dhcp-server in our enviroment, but since the version 4.3 there is an issue with the domain lookup.
We've defined multiple domains in /etc/hosts e.g ldapm.foss-cloud.int or foss-cloud.org.
The problem is now that we get an "Can't contact LDAP server" error, altough the domains are pointing to 127.0.0.1.
So I've done a tcpdump which shows that the DHCP server tries to make requests to an external ip, which is the A-Record of foss-cloud.org
If I now try a domain which points to 127.0.0.1 for example localtest.me, the DHCP server connects without any issues.
Now there is the question how to solve this issue?
For more information here is also a thread on the gentoo forum, where I've put some more details:
Kernel: Linux localhost 4.10.1-gentoo