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TCPDMATCH(8) System Manager's Manual TCPDMATCH(8)


tcpdmatch - tcp wrapper oracle


tcpdmatch [-d] [-i inet_conf] daemon client

tcpdmatch [-d] [-i inet_conf] daemon[@server] [user@]client


tcpdmatch predicts how the tcp wrapper would handle a specific request for service. Examples are given below.

The program examines the tcpd access control tables (default /etc/hosts.allow and /etc/hosts.deny) and prints its conclusion. For maximal accuracy, it extracts additional information from your inetd network configuration file.

When tcpdmatch finds a match in the access control tables, it identifies the matched rule. In addition, it displays the optional shell commands or options in a pretty-printed format; this makes it easier for you to spot any discrepancies between what you want and what the program understands.


The following two arguments are always required:

A daemon process name. Typically, the last component of a daemon executable pathname.
A host name or network address, or one of the `unknown´ or `paranoid´ wildcard patterns.

When a client host name is specified, tcpdmatch gives a prediction for each address listed for that client.

When a client address is specified, tcpdmatch predicts what tcpd would do when client name lookup fails.

Optional information specified with the daemon@server form:

A host name or network address, or one of the `unknown´ or `paranoid´ wildcard patterns. The default server name is `unknown´.

Optional information specified with the user@client form:

A client user identifier. Typically, a login name or a numeric userid. The default user name is `unknown´.


Examine hosts.allow and hosts.deny files in the current directory instead of the default ones.
Specify this option when tcpdmatch is unable to find your inetd.conf network configuration file, or when you suspect that the program uses the wrong one.


To predict how tcpd would handle a telnet request from the local system:

tcpdmatch in.telnetd localhost

The same request, pretending that hostname lookup failed:

tcpdmatch in.telnetd

To predict what tcpd would do when the client name does not match the client address:

tcpdmatch in.telnetd paranoid

On some systems, daemon names have no `in.´ prefix, or tcpdmatch may need some help to locate the inetd configuration file.


The default locations of the tcpd access control tables are:



tcpdchk(8), tcpd configuration checker
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.


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