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Book: LPI Linux Certification in a Nutshell
Section: Chapter 24. Exam 102 Highlighter's Index
24.8 Networking Services 24.8.1 Objective 1: Configure and Manage inetd and Related Services -
inetd is the Internet super daemon; it listens on multiple inbound ports and launches the appropriate child daemon to service the requests. -
inetd uses TCP Wrappers (tcpd) to add access security to services. -
inetd is configured in /etc/inetd.conf. -
You can eliminate an inbound service managed by inetd simply by commenting out its declaration in /etc/inetd.conf and restarting or signaling inetd. -
TCP Wrappers allow the administrator to define access rules for hosts. The configuration files are /etc/hosts.allow and /etc/hosts.deny. 24.8.2 Objective 2: Operate and Perform Basic Configuration of sendmail -
sendmail is a Mail Transfer Agent (MTA). -
sendmail is configured in /etc/sendmail.cf. This file is generally regarded as difficult to configure. -
The "smart host" parameter is used to configure a local sendmail daemon to transfer mail to a site's official mail system. -
/etc/aliases is a file that stores aliases for inbound mail addresses; it can redirect mail to one or more users. -
Whenever /etc/aliases is modified, newaliases must be executed. -
Each user can forward her own mail using a .forward file, containing the forwarding email address, in her home directory. -
Outbound mail that is trapped due to a network or other problem will remain queued; it can be examined using the mailq command. 24.8.3 Objective 3: Operate and Perform Basic Configuration of Apache -
Apache is configured using httpd.conf, srm.conf, and access.conf. On some installations, these may all be combined into httpd.conf. -
The configuration files contain configuration directives, one per line, consisting of a keyword and an argument list. For example: DocumentRoot /home/httpd/html sets the root directory for HTML files on the system. -
Apache is typically started at boot time using the system's startup methods. 24.8.4 Objective 4: Properly Manage the NFS, smb, and nmb Daemons 24.8.4.1 NFS -
Traditional Unix file sharing is done with NFS, originally developed by Sun Microsystems. -
NFS is a client-server package, and any system can hold both roles simultaneously. -
Exporting (sharing) a local filesystem with NFS is done by including a line in the /etc/exports file, consisting of a directory and list of allowed systems, along with NFS options. For example: /usr (ro) orion.mydomain.com(rw) /home *.mydomain.com(rw) 24.8.4.2 Samba -
The Samba suite implements Server Message Block (SMB) protocols used on Microsoft and IBM LANs. -
smbd handles file and printer sharing and authentication. -
nmbd implements the WINS service. -
Samba is configured in /etc/smb.conf. The file consists of sections, each with a series of keyword = value pairs. -
Samba 2.0 and later comes with a web-based configuration tool called SWAT; it is usually configured to be monitored by inetd. 24.8.5 Objective 5: Set Up and Configure Basic DNS Services 24.8.5.1 The resolver -
The resolver is a library used by networked applications when a domain name needs to be translated into an IP address. -
The resolver uses local files, NIS, and DNS to resolve hostnames as directed by /etc/resolv.conf. 24.8.5.2 Domain registration -
Domain names are assigned through a registration process with one of the domain name registrars on the Internet. -
The DNS server daemon is named, part of the BIND package. -
named can be configured to speed up a local system by acting as a non-authoritative caching-only name server. -
named is configured using /etc/named.conf. -
The nslookup , host, and dig utilities can be used to retrieve information from DNS servers. -
BIND Version 4 and Version 8 have significantly different configuration file formats, although the information contained in the files is similar.  | | |
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