resolv_wrapper man page

resolv_wrapper — A wrapper for dns name resolving or dns faking.

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 user@EXAMPLE.COM

Info

2015-08-18