tcpdmatch (8) - Linux Manuals

tcpdmatch: tcp wrapper oracle


tcpdmatch - tcp wrapper oracle


tcpdmatch [-d] daemon client

tcpdmatch [-d] 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 or tlid 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 [at] 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 [at] 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.


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:



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


hosts_access(5), format of the tcpd access control tables.
hosts_options(5), format of the language extensions.