There is a post-script to this issue, following some additional research.
The DNS substitution problem seems to be caused by the router which is treated by some Linuxes as a server (as it should, but isn't always).
The /etc/resolv.conf file may be overwritten at boot time by the /sbin/dhclient-script. To prevent this, simply change the PEERDNS line in /etc/sysconfig/network to read:
There are no side effects that I am aware of, but as usual, make sure it does not affect your network.
Season's greetings