tcpdchk - tcp wrapper configuration checker
tcpdchk [-a] [-d] [-i inet_conf] [-v]
tcpdchk examines your tcp wrapper configuration and reports all potential and real prob-
lems 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 or tlid 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
-d Examine hosts.allow and hosts.deny files in the current directory instead of the
Specify this option when tcpdchk is unable to find your inetd.conf or tlid.conf
network configuration file, or when you suspect that the program uses the wrong
-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 eas-
ier 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.
tlid.conf(5), format of the tlid control file.
Wietse Venema (firstname.lastname@example.org),
Department of Mathematics and Computing Science,
Eindhoven University of Technology
Den Dolech 2, P.O. Box 513,
5600 MB Eindhoven, The Netherlands