TCPDCHK(8) Maintenance Procedures TCPDCHK(8)


tcpdchk - tcp wrapper configuration checker


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


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.


-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


The default locations of the tcpd access control tables are:



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.


Wietse Venema (
Department of Mathematics and Computing Science
Eindhoven University of Technology
Den Dolech 2, P.O. Box 513
5600 MB Eindhoven, The Netherlands


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

|Interface Stability | Committed |

September 15, 2011 TCPDCHK(8)