RESOLV+

RESOLV+

NAME DESCRIPTION CONFIGURATION ENVIRONMENT VARIABLES FILES BUGS AUTHOR SEE ALSO

NAME

resolv+ - enhanced DNS resolver library

DESCRIPTION

Resolv+ is a modified version of the standard Berkeley BIND host resolver library. Enhancements include support for host lookups via the Internet Domain Name System (DNS), the /etc/hosts file, and Sun's Network Information Service (NIS).

The programmer interface to the resolv+ routines is identical to that of the standard resolver library. For further information see the appropriate manual pages.

CONFIGURATION

As with the standard resolver library, the file /etc/resolv.conf must be set up before the resolver can function. In addition, the file /etc/host.conf contains configuration information specific to resolv+.

The host.conf file should contain one configuration keyword per line, followed by appropriate configuration information. The keywords recognized are order , trim , multi , nospoof , and reorder . Each keyword is described seperately below.

order

This keyword specifies how host lookups are to be performed. It should be followed by one or more lookup methods, seperated by commas. Valid methods are bind , hosts and nis .

trim

This keyword may be listed more than once. Each time it should be followed by a single domain name, with the leading dot. When set, the resolv+ library will automatically trim the given domain name from the end of any hostname resolved via DNS. This is intended for use with local hosts and domains. (Related note: trim will not affect hostnames gathered via NIS or the hosts file. Care should be taken to insure that the first hostname for each entry in the hosts file is fully qualified or non-qualified, as appropriate for the local installation.)

multi

Valid values are on and off . If set to /etc/hosts file, instead of only the first. This is off by default, as it may cause a substantial performance loss at sites with large hosts files.

nospoof

Valid values are on and off . If set to rlogin and rsh. It works as follows: after performing a host address lookup, resolv+ will perform a hostname lookup for that address. If the two hostnames do not match, the query will fail.

alert

If this option is set to nospoof option is also set, resolv+ will log a warning of the error via the syslog'' facility. The default value is off.

reorder

Valid values are on and off . If set to ''

ENVIRONMENT VARIABLES

The following environment variables may be set to override resolv+'s configured behavior:

RESOLV_HOST_CONF

If set, it will override the default filename (

RESOLV_SERV_ORDER

If set, will override the

RESOLV_SPOOF_CHECK

If set, will override the spoof check flag. Valid values are

RESOLV_ADD_TRIM_DOMAINS

If set, contains a list of domains to trim that will augment, not supersede, the list in the host.conf file.

RESOLV_OVERRIDE_TRIM_DOMAINS

If set, contains a list of domains to trim that will override those in the host.conf file.

RESOLV_MULTI

If set, overrides the

RESOLV_REORDER

If set, overrides the

FILES

/etc/host.conf, /etc/hosts

BUGS

Quite possibly.

AUTHOR

The original BIND resolver library comes from the University of California at Berkeley's Computer Science Research Group. The original resolv+ modifications were made by Bill Wisner

SEE ALSO

resolver(3), resolver(5), hosts(5), hostname(7), named(8)