TCPDCHK(8) Maintenance Commands and Procedures TCPDCHK(8)

NAME

tcpdchk - tcp wrapper configuration checker

SYNOPSIS

tcpdchk [-a] [-d] [-i inet_conf] [-v]

DESCRIPTION

tcpdchk examines your tcp wrapper configuration and reports all
potential and real problems it can find. The program examines the
tcpd access control files (by default, these are /etc/hosts.allow and
/etc/hosts.deny), and compares the entries in these files against
entries in the inetd network configuration files.

tcpdchk reports problems such as non-existent pathnames; services
that appear in tcpd access control rules, but are not controlled by
tcpd; services that should not be wrapped; non-existent host names or
non-internet address forms; occurrences of host aliases instead of
official host names; hosts with a name/address conflict;
inappropriate use of wildcard patterns; inappropriate use of NIS
netgroups or references to non-existent NIS netgroups; references to
non-existent options; invalid arguments to options; and so on.

Where possible, tcpdchk provides a helpful suggestion to fix the
problem.

OPTIONS

-a Report access control rules that permit access without an
explicit ALLOW keyword. This applies only when the extended
access control language is enabled (build with
-DPROCESS_OPTIONS).

-d Examine hosts.allow and hosts.deny files in the current
directory instead of the default ones.

-i inet_conf
Specify this option when tcpdchk is unable to find your
inetd.conf network configuration file, or when you suspect
that the program uses the wrong one.

-v Display the contents of each access control rule. Daemon
lists, client lists, shell commands and options are shown in a
pretty-printed format; this makes it easier for you to spot
any discrepancies between what you want and what the program
understands.

FILES

The default locations of the tcpd access control tables are:

/etc/hosts.allow
/etc/hosts.deny

SEE ALSO

tcpdmatch(8), explain what tcpd would do in specific cases.
hosts_access(5), format of the tcpd access control tables.
hosts_options(5), format of the language extensions.
inetd.conf(5), format of the inetd control file.
inetd(8), how to invoke tcpd from inetd using the libwrap library.
inetadm(8), managing inetd services in the Service Management Framework.

AUTHORS

Wietse Venema (wietse@wzv.win.tue.nl)
Department of Mathematics and Computing Science
Eindhoven University of Technology
Den Dolech 2, P.O. Box 513
5600 MB Eindhoven, The Netherlands

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+====================+=================+
|Interface Stability | Committed |
+--------------------+-----------------+
March 5, 2025 TCPDCHK(8)