hi,

can give me the steps to config dhcp ina linux server for local lan and assign the preferred dns server.

You need to install the DHCP server package for your distribution (in Fedora "yum install dhcp" should do it if it's not already installed). Once you have it installed, edit the /etc/dhcpd.conf file to configure the parameters (range, name servers, etc.), and then start the service. The /etc/dhcpd.conf file is well documented. If you type "man dhcpd.conf" (no quotes) in the command line you can read the manual page, which describes the syntax and gives examples. For instance, you use the "option domao-name-servers" configuration directive to set which DNS servers are given out to clients.