DESCRIPTION

dqcache is recursive DNS server derived from dnscache (https://cr.yp.to/djbdns/dnscache.html)

CONFIGURATION

dqcache runs chrooted in the directory specified by the $ROOT environment variable, under the uid and gid specified by the $UID and $GID environment variables.

dqcache listens for incoming UDP packets and TCP connections addressed to port 53 of $IP. Typically $IP is 127.0.0.1, but it can also be an externally accessible IP address.

dqcache accepts connections from localhost (127.0.0.0/8 or ::1/128). For external connections dqcache has file-style accesslist.

e.g. for IPv4 address 1.2.3.4 dqcache allows connection when sees a file named:
ip4/1.2.3.4 or
ip4/1.2.3 or
ip4/1.2 or
ip4/1
e.g. for IPv6 address 2a02:598:7000:101:12dd:b1ff:fede:3476 dqcache allows connection when sees a file named:
ip6/2a02:598:7000:101:12dd:b1ff:fede:3476 or
ip6/2a02:598:7000:101:12dd:b1ff:fede or 
ip6/2a02:598:7000:101:12dd:b1ff or
ip6/2a02:598:7000:101:12dd or
ip6/2a02:598:7000:101 or
ip6/2a02:598:7000 or
ip6/2a02:598 or
ip6/2a02

Warning , dqcache encrypts DNS packets and should run on client's machine. If You run dqcache on external IP (not on localhost), You're probably doing it wrong.

dqcache sends outgoing IPv4 packets from high ports of $IPSEND4. Typically $IPSEND4 is 0.0.0.0, meaning the machine's primary IPv4 address.

dqcache sends outgoing IPv6 packets from high ports of $IPSEND6. Typically $IPSEND6 is ::, meaning the machine's primary IPv6 address.

If $HIDETTL is set, dqcache always uses a TTL of 0 in its responses

If $DISABLEIPV6 is set, dqcache sends queries only using IPV4

dqcache reads a list of root servers as an anchor, one record per line, from servers/@. The record has format {IP} or {IP}|{DNSCURVEPUBLICKEY} e.g.:

servers/@:
198.41.0.4
2001:503:ba3e::2:30
192.228.79.201
2001:500:84::b
etc.

dqcache also scans the servers directory for anchors for other domains, one record per line. The record has format {IP} or {IP}|{DNSCURVEPUBLICKEY} e.g.:

 servers/dnscurve.cz:
 185.66.36.55|uz5mj60yr9tnudkkpcglw1y0w6dlh78j1l4gk4z7t8bsf1u4d48wlq
 37.157.196.86|uz5mj60yr9tnudkkpcglw1y0w6dlh78j1l4gk4z7t8bsf1u4d48wlq
 2a02:2b88:2:1::127d:1|uz5mj60yr9tnudkkpcglw1y0w6dlh78j1l4gk4z7t8bsf1u4d48wlq
 2a03:1e20:0:5::2|uz5mj60yr9tnudkkpcglw1y0w6dlh78j1l4gk4z7t8bsf1u4d48wlq

dqcache supports forward-only mode. If $FORWARDONLY is set, dqcache treats servers/@ as a list of IP addresses for other caches, not root servers. It forwards queries to those caches the same way that a client does, rather than contacting a chain of servers according to NS records.

dqcache uses a fixed-size cache, as controlled by the $CACHESIZE environment variable. Typically $CACHESIZE is 10000000 (10MB).

dqcache typically generates new secret key at start of program. If environment variable $SECRETKEY is set, then dqcache loads this secret key. $SECRETKEY must be safely generated using dqcache-makekey(1).

Note that dqcache uses internally two secret keys, one used as the discrete logarithm of the public key (256bit DNSCurve key) and one to encrypt the nonce (128bit TEA symetric key). Both of these keys are actually derived from $SECRETKEY using crypto_stream_salsa20().

dqcache also supports nonce-separation via environment variable $NONCESTART. This means that several caches share a key but use separate nonces:

e.g.:
NONCESTART=100 ... the first of four caches is configured to use top bits 100
NONCESTART=101 ... the second is configured to use top bits 101
NONCESTART=110 ... the third is configured to use top bits 110
NONCESTART=111 ... and the fourth is configured to use top bits 111.
etc.

dqcache typically supports DNSCurve in 'combined mode' (meaning: if Streamlined query fails, dqcache tries also TXT query). Environment variable $DNSCURVETYPE selects specific DNSCurve type.

DNSCURVETYPE=1 ... Streamlined only DNSCurve
DNSCURVETYPE=2 ... TXT only DNSCurve