Como añadir servidores DNS en el servicio DNSCrypt-v2?

Lo primero que necesitas hacer es ir a la configuración de DNSCrypt Proxy que está en /etc/dnscrypt-proxy/dnscrypt-proxy.toml, bajas hasta la sección ##[SERVERS]##,  eliminas todo lo que haya por debajo de la línea "## expiring after `refresh_delay` hours." y añades las siguientes líneas:

[sources]

  ## An example of a remote source from https://github.com/DNSCrypt/dnscrypt-resolvers

  [sources.'public-resolvers']
  urls = ['https://raw.githubusercontent.com/DNSCrypt/dnscrypt-resolvers/master/v2/public-resolvers.md', 'https://download.dnscrypt.info/resolvers-list/v2/public-resolvers.md']
  cache_file = '/var/cache/dnscrypt-proxy/public-resolvers.md'
  minisign_key = 'RWQf6LRCGA9i53mlYecO4IzT51TGPpvWucNSCh1CBM0QTaLn73Y7GFO3'
  refresh_delay = 72
  prefix = ''

Una vez que finalizas esto, DNSCrypt se encargará de buscar el servidor apropiado dentro de la lista dependiendo del tiempo de ping.

Adicionalmente si deseas usar solo unos servidores especificos puedes usar la sección "##dnscrypt-proxy configuration##" al inicio del archivo y añadir el nombre de los que deseas usar, un ejemplo de configuración es este:

##############################################
#                                            #
#        dnscrypt-proxy configuration        #
#                                            #
##############################################

## This is an example configuration file.
## You should adjust it to your needs, and save it as "dnscrypt-proxy.toml"
##
## Online documentation is available here: https://dnscrypt.info/doc



##################################
#         Global settings        #
##################################

## List of servers to use
##
## Servers from the "public-resolvers" source (see down below) can
## be viewed here: https://dnscrypt.info/public-servers
##
## If this line is commented, all registered servers matching the require_* filters
## will be used.
##
## The proxy will automatically pick the fastest, working servers from the list.
## Remove the leading # first to enable this; lines starting with # are ignored.

server_names = ['securedns', 'cloudflare']


## List of local addresses and ports to listen to. Can be IPv4 and/or IPv6.
## Note: When using systemd socket activation, choose an empty set (i.e. [] ).

listen_addresses = []


## Maximum number of simultaneous client connections to accept

max_clients = 250


## Require servers (from static + remote sources) to satisfy specific properties

# Use servers reachable over IPv4
ipv4_servers = true

# Use servers reachable over IPv6 -- Do not enable if you don't have IPv6 connectivity
ipv6_servers = false

# Use servers implementing the DNSCrypt protocol
dnscrypt_servers = true

# Use servers implementing the DNS-over-HTTPS protocol
doh_servers = true


## Require servers defined by remote sources to satisfy specific properties

# Server must support DNS security extensions (DNSSEC)
require_dnssec = false

# Server must not log user queries (declarative)
require_nolog = true

# Server must not enforce its own blacklist (for parental control, ads blocking...)
require_nofilter = true



## Always use TCP to connect to upstream servers

force_tcp = false


## How long a DNS query will wait for a response, in milliseconds

timeout = 2500


## Keepalive for HTTP (HTTPS, HTTP/2) queries, in seconds

keepalive = 30


## Load-balancing strategy: 'p2' (default), 'ph', 'fastest' or 'random'

# lb_strategy = 'p2'


## Log level (0-6, default: 2 - 0 is very verbose, 6 only contains fatal errors)

# log_level = 2


## log file for the application

# log_file = '/var/log/dnscrypt-proxy/dnscrypt-proxy.log'


## Use the system logger (syslog on Unix, Event Log on Windows)

use_syslog = true


## Delay, in minutes, after which certificates are reloaded

cert_refresh_delay = 240


## DNSCrypt: Create a new, unique key for every single DNS query
## This may improve privacy but can also have a significant impact on CPU usage
## Only enable if you don't have a lot of network load

# dnscrypt_ephemeral_keys = false


## DoH: Disable TLS session tickets - increases privacy but also latency

# tls_disable_session_tickets = false


## DoH: Use a specific cipher suite instead of the server preference
## 49199 = TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
## 49195 = TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
## 52392 = TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305
## 52393 = TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305
##
## On non-Intel CPUs such as MIPS routers and ARM systems (Android, Raspberry Pi...),
## the following suite improves performance.
## This may also help on Intel CPUs running 32-bit operating systems.
##
## Delete or comment the next line if you have issues fetching sources or
## connecting to some DoH servers. Google and Cloudflare are fine with it.

# tls_cipher_suite = [52392, 49199]


## Fallback resolver
## This is a normal, non-encrypted DNS resolver, that will be only used
## for one-shot queries when retrieving the initial resolvers list, and
## only if the system DNS configuration doesn't work.
## No user application queries will ever be leaked through this resolver,
## and it will not be used after IP addresses of resolvers URLs have been found.
## It will never be used if lists have already been cached, and if stamps
## don't include host names without IP addresses.
## It will not be used if the configured system DNS works.
## A resolver supporting DNSSEC is recommended. This may become mandatory.
##
## People in China may need to use 114.114.114.114:53 here.
## Other popular options include 8.8.8.8 and 1.1.1.1.

fallback_resolver = '9.9.9.9:53'


## Never try to use the system DNS settings; unconditionally use the
## fallback resolver.

ignore_system_dns = false


## Automatic log files rotation

# Maximum log files size in MB
log_files_max_size = 10

# How long to keep backup files, in days
log_files_max_age = 7

# Maximum log files backups to keep (or 0 to keep all backups)
log_files_max_backups = 1



#########################
#        Filters        #
#########################

## Immediately respond to IPv6-related queries with an empty response
## This makes things faster when there is no IPv6 connectivity, but can
## also cause reliability issues with some stub resolvers. In
## particular, enabling this on macOS is not recommended.

block_ipv6 = false



##################################################################################
#        Route queries for specific domains to a dedicated set of servers        #
##################################################################################

## Example map entries (one entry per line):
## example.com 9.9.9.9
## example.net 9.9.9.9,8.8.8.8,1.1.1.1

# forwarding_rules = '/etc/dnscrypt-proxy/forwarding-rules.txt'



###############################
#        Cloaking rules       #
###############################

## Cloaking returns a predefined address for a specific name.
## In addition to acting as a HOSTS file, it can also return the IP address
## of a different name. It will also do CNAME flattening.
##
## Example map entries (one entry per line)
## example.com     10.1.1.1
## www.google.com  forcesafesearch.google.com

# cloaking_rules = '/etc/dnscrypt-proxy/cloaking-rules.txt'



###########################
#        DNS cache        #
###########################

## Enable a DNS cache to reduce latency and outgoing traffic

cache = true


## Cache size

cache_size = 512


## Minimum TTL for cached entries

cache_min_ttl = 600


## Maximum TTL for cached entries

cache_max_ttl = 86400


## TTL for negatively cached entries

cache_neg_ttl = 60



###############################
#        Query logging        #
###############################

## Log client queries to a file

[query_log]

  ## Path to the query log file (absolute, or relative to the same directory as the executable file)

  # file = '/var/log/dnscrypt-proxy/query.log'


  ## Query log format (currently supported: tsv and ltsv)

  format = 'tsv'


  ## Do not log these query types, to reduce verbosity. Keep empty to log everything.

  # ignored_qtypes = ['DNSKEY', 'NS']



############################################
#        Suspicious queries logging        #
############################################

## Log queries for nonexistent zones
## These queries can reveal the presence of malware, broken/obsolete applications,
## and devices signaling their presence to 3rd parties.

[nx_log]

  ## Path to the query log file (absolute, or relative to the same directory as the executable file)

  # file = '/var/log/dnscrypt-proxy/nx.log'


  ## Query log format (currently supported: tsv and ltsv)

  format = 'tsv'



######################################################
#        Pattern-based blocking (blacklists)        #
######################################################

## Blacklists are made of one pattern per line. Example of valid patterns:
##
##   example.com
##   =example.com
##   *sex*
##   ads.*
##   ads*.example.*
##   ads*.example[0-9]*.com
##
## Example blacklist files can be found at https://download.dnscrypt.info/blacklists/
## A script to build blacklists from public feeds can be found in the
## `utils/generate-domains-blacklists` directory of the dnscrypt-proxy source code.

[blacklist]

  ## Path to the file of blocking rules (absolute, or relative to the same directory as the executable file)

  # blacklist_file = '/etc/dnscrypt-proxy/blacklist.txt'


  ## Optional path to a file logging blocked queries

  # log_file = '/var/log/dnscrypt-proxy/blocked.log'


  ## Optional log format: tsv or ltsv (default: tsv)

  # log_format = 'tsv'



###########################################################
#        Pattern-based IP blocking (IP blacklists)        #
###########################################################

## IP blacklists are made of one pattern per line. Example of valid patterns:
##
##   127.*
##   fe80:abcd:*
##   192.168.1.4

[ip_blacklist]

  ## Path to the file of blocking rules (absolute, or relative to the same directory as the executable file)

  # blacklist_file = '/etc/dnscrypt-proxy/ip-blacklist.txt'


  ## Optional path to a file logging blocked queries

  # log_file = '/var/log/dnscrypt-proxy/ip-blocked.log'


  ## Optional log format: tsv or ltsv (default: tsv)

  # log_format = 'tsv'



######################################################
#   Pattern-based whitelisting (blacklists bypass)   #
######################################################

## Whitelists support the same patterns as blacklists
## If a name matches a whitelist entry, the corresponding session
## will bypass names and IP filters.
##
## Time-based rules are also supported to make some websites only accessible at specific times of the day.

[whitelist]

  ## Path to the file of whitelisting rules (absolute, or relative to the same directory as the executable file)

  # whitelist_file = '/etc/dnscrypt-proxy/whitelist.txt'


  ## Optional path to a file logging whitelisted queries

  # log_file = '/var/log/dnscrypt-proxy/whitelisted.log'


  ## Optional log format: tsv or ltsv (default: tsv)

  # log_format = 'tsv'



##########################################
#        Time access restrictions        #
##########################################

## One or more weekly schedules can be defined here.
## Patterns in the name-based blocklist can optionally be followed with @schedule_name
## to apply the pattern 'schedule_name' only when it matches a time range of that schedule.
##
## For example, the following rule in a blacklist file:
## *.youtube.* @time-to-sleep
## would block access to YouTube only during the days, and period of the days
## define by the 'time-to-sleep' schedule.
##
## {after='21:00', before= '7:00'} matches 0:00-7:00 and 21:00-0:00
## {after= '9:00', before='18:00'} matches 9:00-18:00

[schedules]

  # [schedules.'time-to-sleep']
  # mon = [{after='21:00', before='7:00'}]
  # tue = [{after='21:00', before='7:00'}]
  # wed = [{after='21:00', before='7:00'}]
  # thu = [{after='21:00', before='7:00'}]
  # fri = [{after='23:00', before='7:00'}]
  # sat = [{after='23:00', before='7:00'}]
  # sun = [{after='21:00', before='7:00'}]

  # [schedules.'work']
  # mon = [{after='9:00', before='18:00'}]
  # tue = [{after='9:00', before='18:00'}]
  # wed = [{after='9:00', before='18:00'}]
  # thu = [{after='9:00', before='18:00'}]
  # fri = [{after='9:00', before='17:00'}]



#########################
#        Servers        #
#########################

## Remote lists of available servers
## Multiple sources can be used simultaneously, but every source
## requires a dedicated cache file.
##
## Refer to the documentation for URLs of public sources.
##
## A prefix can be prepended to server names in order to
## avoid collisions if different sources share the same for
## different servers. In that case, names listed in `server_names`
## must include the prefixes.
##
## If the `urls` property is missing, cache files and valid signatures
## must be already present; This doesn't prevent these cache files from
## expiring after `refresh_delay` hours.

[sources]

  ## An example of a remote source from https://github.com/DNSCrypt/dnscrypt-resolvers

  [sources.'public-resolvers']
  urls = ['https://raw.githubusercontent.com/DNSCrypt/dnscrypt-resolvers/master/v2/public-resolvers.md', 'https://download.dnscrypt.info/resolvers-list/v2/public-resolvers.md']
  cache_file = '/var/cache/dnscrypt-proxy/public-resolvers.md'
  minisign_key = 'RWQf6LRCGA9i53mlYecO4IzT51TGPpvWucNSCh1CBM0QTaLn73Y7GFO3'
  refresh_delay = 72
  prefix = ''

  ## Another example source, with resolvers censoring some websites not appropriate for children
  ## This is a subset of the `public-resolvers` list, so enabling both is useless

  #  [sources.'parental-control']
  #  urls = ['https://raw.githubusercontent.com/DNSCrypt/dnscrypt-resolvers/master/v2/parental-control.md', 'https://download.dnscrypt.info/resolvers-list/v2/parental-control.md']
  #  cache_file = '/var/cache/dnscrypt-proxy/parental-control.md'
  #  minisign_key = 'RWQf6LRCGA9i53mlYecO4IzT51TGPpvWucNSCh1CBM0QTaLn73Y7GFO3'



## Optional, local, static list of additional servers
## Mostly useful for testing your own servers.

[static]

  # [static.'google']
  # stamp = 'sdns://AgUAAAAAAAAAAAAOZG5zLmdvb2dsZS5jb20NL2V4cGVyaW1lbnRhbA'