Installation guide

Chapter 8. TCP Wrappers and xinetd 123
instances of this service is under a particular threshold, and any other rules specified for that service
or all xinetd services are followed. Once the target service is brought up for the connecting client,
xinetd goes back to sleep, waiting for additional requests for the services it manages.
8.3.1. xinetd Configuration Files
The xinetd service is controlled by the /etc/xinetd.conf file, as well as the various service-
specific files in the /etc/xinetd.d/ directory.
8.3.1.1. /etc/xinetd.conf
The xinetd.conf file is the parent of all xinetd-controlled service configuration files, as the
service-specific files are also parsed every time xinetd starts. By default, xinetd.conf contains
some basic configuration settings that apply to every service. Below is an example of a typical
xinetd.conf:
defaults
{
instances = 60
log_type = SYSLOG authpriv
log_on_success = HOST PID
log_on_failure = HOST
cps = 25 30
}
includedir /etc/xinetd.d
These lines control various aspects of xinetd:
• instances — Sets the maximum number of requests a particular service can handle at once.
• log_type — Tells xinetd to use the authpriv log, specified in /etc/syslog.conf
and set to /var/log/secure by default, rather than using another specific file. Using
FILE /var/log/xinetdlog here instead would move xinetd logging to a separate
/var/log/xinetdlog file.
• log_on_success — Lets xinetd know what to log if the connection is successful. By default,
the remote host’s IP address and the process ID of server processing the request are recorded.
• log_on_failure — Tells xinetd what to log if the connection fails or is not allowed.
• cps — Tells xinetd to allow no more than 25 connections per second to a given service. If this
limit is reached, the service is retired for 30 seconds.
Note
Both the log_on_success and log_on_failure settings in /etc/xinetd.conf are often modified
by each service, meaning that successful and failed connections will usually log more information
than is indicated in /etc/xinetd.conf.
Various logging options are available in /etc/xinetd.conf and the service-specific xinetd con-
figuration files:
• ATTEMPT — Logs the fact that a failed attempt was made. (log_on_failure)
• DURATION — Logs the length of time the service is used by a remote system. (log_on_success)