In my office, I have AT&T Uverse. The router is a 2wire 3600HGV. The WiFI is provided by a Cisco Linksys E1000 that is plugged in the 2wire device.
With my notebook running Ubuntu 12.04 LTS 64bit, I have both the eth0 (192.168.1.66/24) and eth1 (10.0.0.124/24). Both are managed via DHCP. Whether I have an Ethernet cable plugged in or not, DNS works.
I just got a used netbook. I installed CentOS 6.5 on it using a DVD with a minimal desktop. By default the NetworkManager manages the wlan0. DNS works. I manually configured a static IP for the wired interface. As soon as I enabled the interface, DNS stops working. I dug around the system and searched the Internet looking for answers but haven't found a clue.
Would be appreciative for any hints.