NAME¶

dnscrypt-proxy - A DNSCrypt forwarder

SYNOPSIS¶

dnscrypt-proxy <config file>

dnscrypt-proxy [<option>, ...]

DESCRIPTION¶

dnscrypt-proxy accepts DNS requests, authenticates and encrypts them using dnscrypt and forwards them to a remote dnscrypt-enabled resolver.

Replies from the resolver are expected to be authenticated or else they will be discarded.

The proxy verifies the replies, decrypts them, and transparently forwards them to the local stub resolver.

dnscrypt-proxy listens to 127.0.2.1 / port 53 by default.

OPTIONS (ignored when a configuration file is provided)¶

• -R, --resolver-name=<name>: name of the resolver to use, from the list of available resolvers (see -L). Or random for a random resolver accessible over IPv4, that doesn´t log and supports DNSSEC.
• -a, --local-address=<ip>[:port]: what local IP the daemon will listen to, with an optional port. The default port is 53.
• -d, --daemonize: detach from the current terminal and run the server in background.
• -E, --ephemeral-keys: By default, queries are always sent with the same public key, allowing providers to link this public key to the different IP addresses you are using. This option requires extra CPU cycles, but mitigates this by computing an ephemeral key pair for every query. Use it if you are not using your own server, and the remote server is logging your activity, and your client IP address is frequently changing. Not enabled by default because it may be slow, especially on non-Intel CPUs.
• -K, --client-key=<file>: use a static client secret key stored in <file>.
• -L, --resolvers-list=<file>: path to the CSV file containing the list of available resolvers, and the parameters to use them.
• -l, --logfile=<file>: log events to this file instead of the standard output.
• -m, --loglevel=<level>: don´t log events with priority above this level after the service has been started up. Default is 6, the value for LOG_INFO. Valid values are 0 (system is unusable), 1 (action must be taken immediately), 2 (critical conditions), 3 (error conditions), 4 (warning conditions), 5 (normal but significant condition), 6 (informational) and 7 (debug-level messages).
• -p, --pidfile=<file>: write the PID number to a file.
• -X, --plugin=<plugin_name>[,<options>]: enable a plugin.
• -N, --provider-name=<FQDN>: the fully-qualified name of the dnscrypt certificate provider (for private resolvers).
• -k, --provider-key=<key>: specify the provider public key (for private resolvers).
• -r, --resolver-address=<ip>[:port]: a DNSCrypt-capable resolver IP address with an optional port (for private resolvers). The default port is 443.
• -S, --syslog: if a log file hasn´t been set, log diagnostic messages to syslog instead of printing them. --daemonize implies --syslog.
• -Z, --syslog-prefix=prefix: specify a string of message to insert at the beginning of every line sent to syslog. This implies --syslog.
• -n, --max-active-requests=<count>: set the maximum number of simultaneous active requests. The default value is 250.
• -u, --user=<user name>: chroot(2) to this user´s home directory and drop privileges.
• -t, --test=<margin>: don´t actually start the proxy, but check that a valid certificate can be retrieved from the server and that it will remain valid for the next margin minutes. The exit code is 0 if a valid certificate can be used, 2 if no valid certificates can be used, 3 if a timeout occurred, and 4 if a currently valid certificate is going to expire before margin. The margin is always specified in minutes.
• -T, --tcp-only: always use TCP. A connection made using UDP will get a truncated response, so that the (stub) resolver retries using TCP.
• -e, --edns-payload-size=<bytes>: transparently add an OPT pseudo-RR to outgoing queries in order to enable the EDNS0 extension mechanism. The payload size is the size of the largest response we accept from the resolver before retrying over TCP. This feature is enabled by default, with a payload size of 1252 bytes. Any value below 512 disables it.
• -I, --ignore-timestamps: ignore timestamps when validating certificates. Never enable this option unless you know you really need it (routers without a clock battery).
• -V, --version: show version number.
• -h, --help: show usage.

A public key is 256-bit long, and it has to be specified as a hexadecimal string, with optional columns.

COMMON USAGE EXAMPLE¶

$ dnscrypt-proxy /etc/dnscrypt.conf

COMMON USAGE EXAMPLE WITHOUT A CONFIGURATION FILE¶

$ dnscrypt-proxy --daemonize --resolver-name=...

The resolver name is the first column (Name) in the CSV file.

BUGS AND SUPPORT¶

Please report issues with DNSCrypt itself to https://dnscrypt.org/issues

SEE ALSO¶

hostip(8)