RESOLV_WRAPPER(1) RESOLV_WRAPPER(1) NAME 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 re- solv.conf file is defined in the manpage resolv.conf(5). Currently only the namserver directive is supported. In order that this works with socket_wrapper. The res_* symbols need to be in a separate libresolv library. If they are part of libc this wont work. This is the case with glibc >= 2.34. 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 URI _vpn.cwrap.org https://vpn.cwrap.org/VPN TXT cwrap.org v=spf1 mx 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 RESOLV_WRAPPER_DISABLE_DEEPBIND This allows you to disable deep binding in resolv_wrapper. This is use- ful for running valgrind tools or sanitizers like (address, undefined, thread). 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 AUTHOR The Samba Team 2021-11-03 RESOLV_WRAPPER(1)
NAME | SYNOPSIS | DESCRIPTION | ENVIRONMENT VARIABLES | EXAMPLE | AUTHOR
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