SYNOPSIS
LD_PRELOAD=libresolv_wrapper.so RESOLV_WRAPPER_CONF="/path/to/resolv.conf" ./myapplication
DESCRIPTION
resolv_wrapper makes it possible on most UNIX platforms to contact your own DNS implementation in your test environment. It requires socket_wrapper to be able to contact it. If it doesn't work on a special platform the wrapper is able to fake DNS queries and return valid responses to your application.
- • Redirects name queries to the nameservers specified in your resolv.conf
- • Can fake DNS queries using a simple formatted DNS hosts file.
ENVIRONMENT VARIABLES
RESOLV_WRAPPER_CONF
- This is used to specify the resolv.conf to use. The format of the resolv.conf file is defined in the manpage resolv.conf(5). Currently only the namserver directive is supported.
RESOLV_WRAPPER_HOSTS
-
This environment variable is used for faking DNS queries. It must point to a hosts-like text file that specifies fake records for custom queries. The format of the file looks like this:
-
TYPE RECORD_NAME RECORD_VALUE
-
For example:
-
A dc.cwrap.org 127.0.0.10 AAAA dc.cwrap.org fd00::5357:5f0a CNAME kerberos.cwrap.org dc.cwrap.org SRV _kerberos._tcp.cwrap.org kerberos.cwrap.org 88
RESOLV_WRAPPER_DEBUGLEVEL
-
If you need to see what is going on in resolv_wrapper itself or try to find a bug, you can enable logging support in resolv_wrapper if you built it with debug symbols.
- • 0 = ERROR
- • 1 = WARNING
- • 2 = DEBUG
- • 3 = TRACE
EXAMPLE
The following command would trick kinit(1) into using DNS servers from "./resolv.conf" for Kerberos service resolution:
-
$ LD_PRELOAD=libresolv_wrapper.so RESOLV_WRAPPER_CONF="./resolv.conf" kinit [email protected]