Software
skarnet.org

s6-dns

What is it ?

s6-dns is a suite of DNS client programs and libraries for Unix systems, as an alternative to the BIND, djbdns or other DNS clients.

s6-dns may include its own series of DNS caches and servers at some point in the future.

The s6- prefix is slightly misleading, and probably a naming mistake. This package is not, stricto sensu, a part of the s6 ecosystem, and it is nowhere near a requirement for a s6-based installation. However, it is a requirement for s6-networking, which provides useful networking utilities often used with s6, so keeping the prefix makes some kind of sense; you can see s6-dns as an extension to the s6 ecosystem.

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• Why a separate client library ? Why not just use getaddrinfo() ?
• What is wrong with libresolv, BIND's client library ?

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Installation

Requirements

• A POSIX-compliant system with a standard C development environment
• GNU make, version 3.81 or later
• skalibs version 2.15.0.0 or later. It's a build-time requirement. It's also a run-time requirement if you link against the shared version of the skalibs library.

Licensing

s6-dns is free software. It is available under the ISC license.

Download

• The current released version of s6-dns is 2.4.1.2. You can access its checksum here.
• Alternatively, you can checkout a copy of the s6-dns git repository:

   git clone git://git.skarnet.org/s6-dns 

• There's also a Codeberg mirror, or a GitHub mirror, or a SourceHut mirror of the s6-dns git repository.

Compilation

• See the enclosed INSTALL file for installation details.

Upgrade notes

• This page lists the differences to be aware of between the previous versions of s6-dns and the current one.

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Reference

Commands

All these commands exit 111 if they encounter a temporary error or hardware error, and 100 if they encounter a permanent error - such as a misuse. Short-lived commands exit 0 on success. Other exit codes are documented in the relevant page.

Command-line DNS clients programs

• The s6-dnsip program
• The s6-dnsip4 program
• The s6-dnsip6 program
• The s6-dnsname program
• The s6-dnsmx program
• The s6-dnsns program
• The s6-dnssoa program
• The s6-dnssrv program
• The s6-dnstxt program

Filtering tools

• The s6-dnsip4-filter program
• The s6-dnsip6-filter program
• The s6-dnsname-filter program

Command-line qualification

• The s6-dnsqualify program

DNS analysis and debug tools

• The s6-dnsq program
• The s6-dnsqr program

Miscellaneous utilities

• The s6-randomip program
• The s6-dns-hosts-compile program

Libraries

Protocol implementation and synchronous resolution

• The s6dns library interface

Asynchronous resolution

• The skadns library interface

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Related resources

s6-dns discussion

• s6-dns is discussed on the skaware mailing-list.
• It can also be discussed on the cr.yp.to dns mailing-list.

Similar work

• BIND is the most widely used DNS software suite on the Internet. It's also arguably the most buggy, convoluted and impossible to understand.
• djbdns is DJB's DNS suite. It works very well, but is unfortunately unmaintained by the author. s6-dns follows the same design principles.