Two-Minute Drill

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Here are some of the key points from the certification objectives in Chapter 9.


  • DNS, the Domain Name System, includes a database of computer names and IP addresses.

  • DNS is based on the Berkeley Internet Name Domain (BIND), using the named daemon.

  • Critical DNS configuration files include /etc/named.conf and the files in the /var/named directory.

  • Caching-only DNS servers store requests and their associated IP addresses on a computer.

  • Every time you change DNS, remember to update the serial number in your zone file. Otherwise, other DNS servers don't realize that you've changed anything.

Network File System (NFS)

  • NFS is the standard for sharing files and printers between Linux and Unix computers.

  • Key NFS processes are rpc.mountd for mount requests, rpc.rquotad for quota requests and nfsd for each network share.

  • NFS shares are configured in /etc/exports and activated with the exportfs -a command.

  • Clients can make permanent connections for NFS shares through /etc/fstab.

  • If an NFS server fails, it can 'hang' an NFS client. When possible, avoid using NFS on mission-critical computers.

  • NFS and portmap have security problems. Limit their use when possible to secure internal networks protected by an appropriate firewall.


  • DHCP (Dynamic Host Configuration Protocol) allows a client computer to obtain network information (such as an IP number) from a server.

  • The bootp protocol allows a client computer to access a DHCP server on a remote network.

  • DHCP servers are configured through /etc/dhcpd.conf.

  • Remember that the DHCP server daemon is dhcpd; the DHCP client daemon is dhclient.

Keeping Servers in Sync

  • You can keep the time on a server in sync with UTC using the Network Time Protocol (NTP).

  • The configuration file for NTP is /etc/ntp.conf.

  • The Red Hat Date/Time Configuration tool is a GUI utility that can help you configure /etc/ntp.conf.

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RCHE Red Hat Certified Engineer Linux Study Guide[c] Exam (Rh302)
RCHE Red Hat Certified Engineer Linux Study Guide[c] Exam (Rh302)
ISBN: 71765654
Year: 2003
Pages: 194 © 2008-2017.
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