Simple authoritative DNS server, suitable for embedded systems.

Building emdns

Current implementation can be compiled under Linux/Unix using make:

make

or manually:

gcc *.c -o emdns

Running emdns

The compiled executable can be run directly:

./emdns < sample.zone

Default port is 5959 UDP.

You can send a query using dig as follows:

dig @127.0.0.1 -p 5959 subdomain.sample.com

If you use the sample zone file this would return:

subdomain.sample.com.   0       IN      CNAME   mail2.sample.com.
mail2.sample.com.       0       IN      CNAME   mail.sample.com.
mail.sample.com.        0       IN      A       192.0.2.3

Compile options

EMDNS_SUPPORT_ALL_CLASSES By default only IN (Internet) class is used. If you want to enable all classes, you can do it by setting the EMDNS_SUPPORT_ALL_CLASSES define when compiling:

make CFLAGS=-DEMDNS_SUPPORT_ALL_CLASSES

Keep in mind that this changes the interface and adds an additional parameter (the class) to some of the functions.

EMDNS_DISABLE_ALIAS_RESOLVING By default aliases (CNAME records) are automatically resolved and included in the response. This results in less requests, but slightly increased memory requirement for the response buffer. You can disable the automatic alias resolving by setting the EMDNS_SUPPORT_ALL_CLASSES define:

make CFLAGS=-DEMDNS_DISABLE_ALIAS_RESOLVING

EMDNS_ENABLE_LOGGING If you want to enable logging of additional information on stdout, set the EMDNS_ENABLE_LOGGING define:

make CFLAGS=-DEMDNS_ENABLE_LOGGING

Stability and open issues

This software is still under development, therefore it is not considered stable and might not function properly. If you have problems, feel free to open an issue.