NAME
oidentd.conf - The oidentd configuration file.
DESCRIPTION
The oidentd configuration file is used to specify the amount of control
users have over the responses oidentd returns upon successful lookups
for connections owned by them.
The $HOME/.oidentd.conf file allows a user to specify what ident
response will be returned for specific connections.
/etc/oidentd.conf SYNTAX
USER DIRECTIVE
The oidentd.conf file consists of 0 or more user directives. The
user directive is used to grant capabilities on a per-user
basis.
The user directive has the following syntax:
default {
<range directive>
}
OR
user <username> {
<range directive>
}
The default directive matches all users for whom rules are not
defined. There should only be one default directive, and it
should be the first statement in the file. All entries for users
defined after the default definition will inherit the
capabilities of the default user. Capabilities can then be
allowed, denied, or forced on a per-user basis by way of the
user statement followed by the username of the user to whom the
properties that follow will apply.
RANGE DIRECTIVE
The body of a user directive consists of 1 or more range
directives.
The range directive is used to specify a host/port range for
which a set of capabilities is binding. A range directive
consists of 1 or more statements of the following form:
default {
<capability directive>
}
OR
to <host> lport <lport> from <host> fport <fport> {
<capability directive>
}
The default directive matches all host/port pairs for which
rules are not defined. There should only be one default
directive, and it should be the first statement in the block.
Anywhere from 1 to all 4 of the to, lport, from, and fport
parameters may be specified.
The to parameter is used to specify the address to which a
connection is made.
The from parameter is used to specify the address from which a
connection originates. It may be useful to specify this address
when a system has more than 1 IP address.
The to and from parameters take either an IP address or a
hostname argument.
The lport parameter is used to specify the local port from which
a connection originates.
The fport parameter is used to specify the destination port of a
connection.
The lport and fport parameters take either a port or a port
range. Ports can be specified numerically (e.g. 113) or by
giving a service name (e.g. "auth"). Ranges of ports take the
form <starting port>:<ending port>. The ending port is optional.
If the ending port is omitted, the range is taken to be any port
greater than or equal to the starting port.
The omission of any of the to, lport, from and fport parameters
acts like a wildcard for that parameter. For example, the
statement "from localhost" matches all connections from
localhost on any port to any host on any port.
CAPABILITY DIRECTIVE
The body of a range directive consists of one or more capability
directives.
Capabilities are used to assign or deny privileges to specific
users. Valid capabilities inside user directives are allow,
deny, andforce.
The capability directive consists of one or more statements of
the form:
allow OR deny OR force <capability>.
The capability argument must be one of the capabilities
described in the capability section below.
The force action takes a third argument when the capability is
reply. For example, force reply "randomuser".
$HOME/.oidentd.conf SYNTAX
A user’s .oidentd.conf configuration file may contain 0 or more of the
following statements:
global {
<capability>
}
OR
<range directive> {
<capability>
}
The global directive acts as a wildcard, matching all connections, so
if used at all, the global directive should be the first entry in the
file and should be used only once. Use is permitted anywhere in the
file and infinitely many times, however it doesn’t make much sense to
use it in this manner.
The range directive has the same syntax and semantics as the range
directive in the /etc/oidentd.conf file. See above for a description.
Valid capabilities are reply, random, numeric, random_numeric, and
hide. Descriptions can be found below.
CAPABILITIES
spoof Allow spoofed ident responses; allow the user to specify a
string of her choosing as the ident reply. The only restriction
on the spoofed response is that it must not be the username of
another user. When a user spoofs her ident reply, the login name
of the user is recorded along with the forged reply.
This capability does not apply to the force action.
spoof_all
Allow the usernames of other users to be used as ident
responses.
This capability does not apply to the force action.
spoof_privport
Allow ident replies to be spoofed on privileged ports (ports
lower than 1024).
This capability does not apply to the force action.
reply <string> [<string1> ... <stringN>]
Reply to successful ident lookups with the ident response
specified in <string>. If more than one string parameter is
given, one of the strings will be selected randomly.
In a user’s $HOME/.oidentd.conf file, up to 20 strings may be
specified for a reply statement.
In the /etc/oidentd.conf file, there is no limitation on the
number of strings that may be specified.
The strings must be quoted strings (e.g. "string"). Strings may
contain the following escape characters:
\n new line
\t tab
\r carriage return
\b backspace
\v vertical tab
\f form feed
\a alert (bell)
\e escape
\\ backslash
\NNN The character with the ASCII code NNN in the octal base
system.
\xNNN The character with the ASCII code NNN in the hexadecimal
base system.
This capability only applies to the force action.
hide Hide the user; report a "HIDDEN-USER" error when an ident lookup
succeeds.
random Reply to successful ident lookups with a randomly generated
ident response of consisting of alphanumeric characters.
numeric
Reply to successful ident lookups with the UID of the user that
was looked up.
random_numeric
Reply to successful with a randomly generated ident response of
the form userN, where N is a random number between 0 and 100000.
EXAMPLE /etc/oidentd.conf FILE
default {
default {
deny spoof
deny spoof_all
deny spoof_privport
allow random_numeric
allow numeric
allow hide
}
}
Grant all users the ability to generate random numeric ident replies,
the ability to generate numeric ident replies and the ability to hide
their identities on all ident queries. Explicitly deny the ability to
spoof ident responses.
user root {
default {
force reply "UNKNOWN"
}
}
Reply with "UNKNOWN" for all successful ident queries for root.
user ryan {
default {
allow spoof
allow spoof_all
allow random
allow hide
}
from 127.0.0.1 {
allow spoof_privport
}
}
Grant the user "ryan" the capability to spoof ident replies, including
the ability to use other usernames as ident replies, generate random
replies and hide his ident for all connections, and grant the user
"ryan" the capability to spoof ident replies to privileged ports (<
1024) on connections originating from the host 127.0.0.1.
EXAMPLE $HOME/.oidentd.conf FILE
global {
reply "unknown"
}
Reply with "unknown" to all successful ident lookups.
to irc.example.org {
reply "example"
}
Reply with "example" to ident lookups for connections to
irc.example.org.
AUTHOR
Ryan McCabe <ryan@numb.org>
http://dev.ojnk.net
SEE ALSO
oidentd(8) oidentd_masq.conf(5)