YPSERV.ACL(5)

NAME
ypserv.acl - ypserv(8) configuration file

DESCRIPTION
The ypserv.acl file controls which hosts can connect to the YP server.

The format is more complex than the format for securenet(5). The first two verbs on each line controls if the line will allow or deny access for a host, network (net) or all hosts.

The YP server reads the configuration file and build a list in memory. This list is processed from the beginning for every incomming request. As soon a match is found in the list the search terminates and it returns success or failure depending on allow or deny. If no match was found in the list success is returned.

If access is denied every call will cause a “no such domain” error for the caller.

There is no default name for this file. Start ypserv with a -a filename to read a file with this format.

The following different syntax can be used:

<allow|deny> host <hostname|ip-address>

If hostname has more than one ip address then all will be added to the list.

<allow|deny> net <netname|netnumber> [netmask <netname|netnumber>]

If the netmask part of the command isn't given then the netmask will be assumed to be a class A, B or C net depending on the net number.

<allow|deny> all

A line containing one of these commands will always match any host.

EXAMPLES

A configuration file might appear as follows:

    # This is an example of an access control file to be used by ypserv.
    #
    # This file is parsed line by line. First match will terminate the check
    # of the caller.
    #
    ###########################################################################
    # This is the commands that will match a single host
    #
    #	allow host <hostname|ip-address>
    #	deny host <hostname|ip-address>
    #
    # To process hostname gethostbyname is called. If the hostname has
    # multiple ip-addresses all will be added (I hope). ip-address
    # processed by inet_aton.
    deny host jodie
    ###########################################################################
    # This is the commands that will match a network
    #
    #	allow net <netname|netnumber> [netmask <netname|netnumber>]
    #	deny net <netname|netnumber> [netmask <netname|netnumber>]
    #
    # To process netname getnetbyname is called, and inet_aton is used for
    # netnumber. inet_aton both access numbers as 255.255.255.0 and 0xffffff00.
    #
    # If netmask isn't given the parser will assume netmask from the first bits
    # of the network number. So if the network is subneted the you have to add
    # the netmask. In my case I've got the network 139.58.253.0 at home so too
    # allow any of my computers to talk with the server I need the following
    # line
    #
    allow net mojathome netmask 255.255.255.0
    ###########################################################################
    # At last we have a command that will match any caller:
    #
    #	allow all
    #	deny all
    #
    # reject all connections
    deny all

FILES
/var/yp/ypserv.acl
    A ypserv(8) configuration file.

SEE ALSO
securenet(5), yp(8), ypserv(8)

AUTHOR
Mats O Jansson <moj@stacken.kth.se>