Configuration
This chapter describes all configuration options in config.yaml
. You can download a reference file with all
configuration properties as JSON.
reference configuration file
# REVIEW: manual changelog entry
upstreams:
groups:
# these external DNS resolvers will be used. Blocky picks 2 random resolvers from the list for each query
# format for resolver: [net:]host:[port][/path]. net could be empty (default, shortcut for tcp+udp), tcp+udp, tcp, udp, tcp-tls or https (DoH). If port is empty, default port will be used (53 for udp and tcp, 853 for tcp-tls, 443 for https (Doh))
# this configuration is mandatory, please define at least one external DNS resolver
default:
# example for tcp+udp IPv4 server (https://digitalcourage.de/)
- 5.9.164.112
# Cloudflare
- 1.1.1.1
# example for DNS-over-TLS server (DoT)
- tcp-tls:fdns1.dismail.de:853
# example for DNS-over-HTTPS (DoH)
- https://dns.digitale-gesellschaft.ch/dns-query
# optional: use client name (with wildcard support: * - sequence of any characters, [0-9] - range)
# or single ip address / client subnet as CIDR notation
laptop*:
- 123.123.123.123
# optional: Determines what strategy blocky uses to choose the upstream servers.
# accepted: parallel_best, strict
# default: parallel_best
strategy: parallel_best
# optional: timeout to query the upstream resolver. Default: 2s
timeout: 2s
# optional: If true, blocky will fail to start unless at least one upstream server per group is reachable. Default: false
startVerifyUpstream: true
# optional: Determines how blocky will create outgoing connections. This impacts both upstreams, and lists.
# accepted: dual, v4, v6
# default: dual
connectIPVersion: dual
# optional: custom IP address(es) for domain name (with all sub-domains). Multiple addresses must be separated by a comma
# example: query "printer.lan" or "my.printer.lan" will return 192.168.178.3
customDNS:
customTTL: 1h
# optional: if true (default), return empty result for unmapped query types (for example TXT, MX or AAAA if only IPv4 address is defined).
# if false, queries with unmapped types will be forwarded to the upstream resolver
filterUnmappedTypes: true
# optional: replace domain in the query with other domain before resolver lookup in the mapping
rewrite:
example.com: printer.lan
mapping:
printer.lan: 192.168.178.3,2001:0db8:85a3:08d3:1319:8a2e:0370:7344
# optional: definition, which DNS resolver(s) should be used for queries to the domain (with all sub-domains). Multiple resolvers must be separated by a comma
# Example: Query client.fritz.box will ask DNS server 192.168.178.1. This is necessary for local network, to resolve clients by host name
conditional:
# optional: if false (default), return empty result if after rewrite, the mapped resolver returned an empty answer. If true, the original query will be sent to the upstream resolver
# Example: The query "blog.example.com" will be rewritten to "blog.fritz.box" and also redirected to the resolver at 192.168.178.1. If not found and if `fallbackUpstream` was set to `true`, the original query "blog.example.com" will be sent upstream.
# Usage: One usecase when having split DNS for internal and external (internet facing) users, but not all subdomains are listed in the internal domain.
fallbackUpstream: false
# optional: replace domain in the query with other domain before resolver lookup in the mapping
rewrite:
example.com: fritz.box
mapping:
fritz.box: 192.168.178.1
lan.net: 192.168.178.1,192.168.178.2
# optional: use black and white lists to block queries (for example ads, trackers, adult pages etc.)
blocking:
# definition of blacklist groups. Can be external link (http/https) or local file
blackLists:
ads:
- https://s3.amazonaws.com/lists.disconnect.me/simple_ad.txt
- https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts
- http://sysctl.org/cameleon/hosts
- https://s3.amazonaws.com/lists.disconnect.me/simple_tracking.txt
- |
# inline definition with YAML literal block scalar style
# hosts format
someadsdomain.com
special:
- https://raw.githubusercontent.com/StevenBlack/hosts/master/alternates/fakenews/hosts
# definition of whitelist groups. Attention: if the same group has black and whitelists, whitelists will be used to disable particular blacklist entries. If a group has only whitelist entries -> this means only domains from this list are allowed, all other domains will be blocked
whiteLists:
ads:
- whitelist.txt
- |
# inline definition with YAML literal block scalar style
# hosts format
whitelistdomain.com
# this is a regex
/^banners?[_.-]/
# definition: which groups should be applied for which client
clientGroupsBlock:
# default will be used, if no special definition for a client name exists
default:
- ads
- special
# use client name (with wildcard support: * - sequence of any characters, [0-9] - range)
# or single ip address / client subnet as CIDR notation
laptop*:
- ads
192.168.178.1/24:
- special
# which response will be sent, if query is blocked:
# zeroIp: 0.0.0.0 will be returned (default)
# nxDomain: return NXDOMAIN as return code
# comma separated list of destination IP addresses (for example: 192.100.100.15, 2001:0db8:85a3:08d3:1319:8a2e:0370:7344). Should contain ipv4 and ipv6 to cover all query types. Useful with running web server on this address to display the "blocked" page.
blockType: zeroIp
# optional: TTL for answers to blocked domains
# default: 6h
blockTTL: 1m
# optional: Configure how lists, AKA sources, are loaded
loading:
# optional: list refresh period in duration format.
# Set to a value <= 0 to disable.
# default: 4h
refreshPeriod: 24h
# optional: Applies only to lists that are downloaded (HTTP URLs).
downloads:
# optional: timeout for list download (each url). Use large values for big lists or slow internet connections
# default: 5s
timeout: 60s
# optional: Maximum download attempts
# default: 3
attempts: 5
# optional: Time between the download attempts
# default: 500ms
cooldown: 10s
# optional: Maximum number of lists to process in parallel.
# default: 4
concurrency: 16
# optional: if failOnError, application startup will fail if at least one list can't be downloaded/opened
# default: blocking
strategy: failOnError
# Number of errors allowed in a list before it is considered invalid.
# A value of -1 disables the limit.
# default: 5
maxErrorsPerSource: 5
# optional: configuration for caching of DNS responses
caching:
# duration how long a response must be cached (min value).
# If <=0, use response's TTL, if >0 use this value, if TTL is smaller
# Default: 0
minTime: 5m
# duration how long a response must be cached (max value).
# If <0, do not cache responses
# If 0, use TTL
# If > 0, use this value, if TTL is greater
# Default: 0
maxTime: 30m
# Max number of cache entries (responses) to be kept in cache (soft limit). Useful on systems with limited amount of RAM.
# Default (0): unlimited
maxItemsCount: 0
# if true, will preload DNS results for often used queries (default: names queried more than 5 times in a 2-hour time window)
# this improves the response time for often used queries, but significantly increases external traffic
# default: false
prefetching: true
# prefetch track time window (in duration format)
# default: 120
prefetchExpires: 2h
# name queries threshold for prefetch
# default: 5
prefetchThreshold: 5
# Max number of domains to be kept in cache for prefetching (soft limit). Useful on systems with limited amount of RAM.
# Default (0): unlimited
prefetchMaxItemsCount: 0
# Time how long negative results (NXDOMAIN response or empty result) are cached. A value of -1 will disable caching for negative results.
# Default: 30m
cacheTimeNegative: 30m
# optional: configuration of client name resolution
clientLookup:
# optional: this DNS resolver will be used to perform reverse DNS lookup (typically local router)
upstream: 192.168.178.1
# optional: some routers return multiple names for client (host name and user defined name). Define which single name should be used.
# Example: take second name if present, if not take first name
singleNameOrder:
- 2
- 1
# optional: custom mapping of client name to IP addresses. Useful if reverse DNS does not work properly or just to have custom client names.
clients:
laptop:
- 192.168.178.29
# optional: configuration for prometheus metrics endpoint
prometheus:
# enabled if true
enable: true
# url path, optional (default '/metrics')
path: /metrics
# optional: write query information (question, answer, client, duration etc.) to daily csv file
queryLog:
# optional one of: mysql, postgresql, csv, csv-client. If empty, log to console
type: mysql
# directory (should be mounted as volume in docker) for csv, db connection string for mysql/postgresql
target: db_user:db_password@tcp(db_host_or_ip:3306)/db_name?charset=utf8mb4&parseTime=True&loc=Local
#postgresql target: postgres://user:password@db_host_or_ip:5432/db_name
# if > 0, deletes log files which are older than ... days
logRetentionDays: 7
# optional: Max attempts to create specific query log writer, default: 3
creationAttempts: 1
# optional: Time between the creation attempts, default: 2s
creationCooldown: 2s
# optional: Which fields should be logged. You can choose one or more from: clientIP, clientName, responseReason, responseAnswer, question, duration. If not defined, it logs all fields
fields:
- clientIP
- duration
# optional: Blocky can synchronize its cache and blocking state between multiple instances through redis.
redis:
# Server address and port or master name if sentinel is used
address: redismaster
# Username if necessary
username: usrname
# Password if necessary
password: passwd
# Database, default: 0
database: 2
# Connection is required for blocky to start. Default: false
required: true
# Max connection attempts, default: 3
connectionAttempts: 10
# Time between the connection attempts, default: 1s
connectionCooldown: 3s
# Sentinal username if necessary
sentinelUsername: usrname
# Sentinal password if necessary
sentinelPassword: passwd
# List with address and port of sentinel hosts(sentinel is activated if at least one sentinel address is configured)
sentinelAddresses:
- redis-sentinel1:26379
- redis-sentinel2:26379
- redis-sentinel3:26379
# optional: Mininal TLS version that the DoH and DoT server will use
minTlsServeVersion: 1.3
# if https port > 0: path to cert and key file for SSL encryption. if not set, self-signed certificate will be generated
#certFile: server.crt
#keyFile: server.key
# optional: use these DNS servers to resolve blacklist urls and upstream DNS servers. It is useful if no system DNS resolver is configured, and/or to encrypt the bootstrap queries.
bootstrapDns:
- tcp+udp:1.1.1.1
- https://1.1.1.1/dns-query
- upstream: https://dns.digitale-gesellschaft.ch/dns-query
ips:
- 185.95.218.42
# optional: drop all queries with following query types. Default: empty
filtering:
queryTypes:
- AAAA
# optional: return NXDOMAIN for queries that are not FQDNs.
fqdnOnly:
# default: false
enable: true
# optional: if path defined, use this file for query resolution (A, AAAA and rDNS). Default: empty
hostsFile:
# optional: Hosts files to parse
sources:
- /etc/hosts
- https://example.com/hosts
- |
# inline hosts
127.0.0.1 example.com
# optional: TTL, default: 1h
hostsTTL: 30m
# optional: Whether loopback hosts addresses (127.0.0.0/8 and ::1) should be filtered or not
# default: false
filterLoopback: true
# optional: Configure how sources are loaded
loading:
# optional: file refresh period in duration format.
# Set to a value <= 0 to disable.
# default: 4h
refreshPeriod: 24h
# optional: Applies only to files that are downloaded (HTTP URLs).
downloads:
# optional: timeout for file download (each url). Use large values for big files or slow internet connections
# default: 5s
timeout: 60s
# optional: Maximum download attempts
# default: 3
attempts: 5
# optional: Time between the download attempts
# default: 500ms
cooldown: 10s
# optional: Maximum number of files to process in parallel.
# default: 4
concurrency: 16
# optional: if failOnError, application startup will fail if at least one file can't be downloaded/opened
# default: blocking
strategy: failOnError
# Number of errors allowed in a file before it is considered invalid.
# A value of -1 disables the limit.
# default: 5
maxErrorsPerSource: 5
# optional: ports configuration
ports:
# optional: DNS listener port(s) and bind ip address(es), default 53 (UDP and TCP). Example: 53, :53, "127.0.0.1:5353,[::1]:5353"
dns: 53
# optional: Port(s) and bind ip address(es) for DoT (DNS-over-TLS) listener. Example: 853, 127.0.0.1:853
tls: 853
# optional: Port(s) and optional bind ip address(es) to serve HTTPS used for prometheus metrics, pprof, REST API, DoH... If you wish to specify a specific IP, you can do so such as 192.168.0.1:443. Example: 443, :443, 127.0.0.1:443,[::1]:443
https: 443
# optional: Port(s) and optional bind ip address(es) to serve HTTP used for prometheus metrics, pprof, REST API, DoH... If you wish to specify a specific IP, you can do so such as 192.168.0.1:4000. Example: 4000, :4000, 127.0.0.1:4000,[::1]:4000
http: 4000
# optional: logging configuration
log:
# optional: Log level (one from debug, info, warn, error). Default: info
level: info
# optional: Log format (text or json). Default: text
format: text
# optional: log timestamps. Default: true
timestamp: true
# optional: obfuscate log output (replace all alphanumeric characters with *) for user sensitive data like request domains or responses to increase privacy. Default: false
privacy: false
# optional: add EDE error codes to dns response
ede:
# enabled if true, Default: false
enable: true
# optional: configure optional Special Use Domain Names (SUDN)
specialUseDomains:
# optional: block recomended private TLDs
# default: true
rfc6762-appendixG: true
Basic configuration
Parameter | Type | Mandatory | Default value | Description |
---|---|---|---|---|
certFile | path | no | Path to cert and key file for SSL encryption (DoH and DoT); if empty, self-signed certificate is generated | |
keyFile | path | no | Path to cert and key file for SSL encryption (DoH and DoT); if empty, self-signed certificate is generated | |
dohUserAgent | string | no | HTTP User Agent for DoH upstreams | |
minTlsServeVersion | string | no | 1.2 | Minimum TLS version that the DoT and DoH server use to serve those encrypted DNS requests |
startVerifyUpstream | bool | no | false | If true, blocky will fail to start unless at least one upstream server per group is reachable. |
connectIPVersion | enum (dual, v4, v6) | no | dual | IP version to use for outgoing connections (dual, v4, v6) |
Example
minTlsServeVersion: 1.1
connectIPVersion: v4
Ports configuration
All logging port are optional.
Parameter | Type | Default value | Description |
---|---|---|---|
ports.dns | [IP]:port[,[IP]:port]* | 53 | Port(s) and optional bind ip address(es) to serve DNS endpoint (TCP and UDP). If you wish to specify a specific IP, you can do so such as 192.168.0.1:53 . Example: 53 , :53 , 127.0.0.1:53,[::1]:53 |
ports.tls | [IP]:port[,[IP]:port]* | Port(s) and optional bind ip address(es) to serve DoT DNS endpoint (DNS-over-TLS). If you wish to specify a specific IP, you can do so such as 192.168.0.1:853 . Example: 83 , :853 , 127.0.0.1:853,[::1]:853 |
|
ports.http | [IP]:port[,[IP]:port]* | Port(s) and optional bind ip address(es) to serve HTTP used for prometheus metrics, pprof, REST API, DoH... If you wish to specify a specific IP, you can do so such as 192.168.0.1:4000 . Example: 4000 , :4000 , 127.0.0.1:4000,[::1]:4000 |
|
ports.https | [IP]:port[,[IP]:port]* | Port(s) and optional bind ip address(es) to serve HTTPS used for prometheus metrics, pprof, REST API, DoH... If you wish to specify a specific IP, you can do so such as 192.168.0.1:443 . Example: 443 , :443 , 127.0.0.1:443,[::1]:443 |
Example
ports:
dns: 53
http: 4000
https: 443
Logging configuration
All logging options are optional.
Parameter | Type | Default value | Description |
---|---|---|---|
log.level | enum (debug, info, warn, error) | info | Log level |
log.format | enum (text, json) | text | Log format (text or json). |
log.timestamp | bool | true | Log time stamps (true or false). |
log.privacy | bool | false | Obfuscate log output (replace all alphanumeric characters with *) for user sensitive data like request domains or responses to increase privacy. |
Example
log:
level: debug
format: json
timestamp: false
privacy: true
Upstreams configuration
To resolve a DNS query, blocky needs external public or private DNS resolvers. Blocky supports DNS resolvers with following network protocols (net part of the resolver URL):
- tcp+udp (UDP and TCP, dependent on query type)
- https (aka DoH)
- tcp-tls (aka DoT)
Hint
You can (and should!) configure multiple DNS resolvers.
Per default blocky uses the parallel_best
upstream strategy where blocky picks 2 random resolvers from the list for each query and
returns the answer from the fastest one.
Each resolver must be defined as a string in following format: [net:]host:[port][/path][#commonName]
.
Parameter | Type | Mandatory | Default value |
---|---|---|---|
net | enum (tcp+udp, tcp-tls or https) | no | tcp+udp |
host | IP or hostname | yes | |
port | int (1 - 65535) | no | 53 for udp/tcp, 853 for tcp-tls and 443 for https |
commonName | string | no | the host value |
The commonName
parameter overrides the expected certificate common name value used for verification.
Note
Blocky needs at least the configuration of the default group with at least one upstream DNS server. This group will be used as a fallback, if no client specific resolver configuration is available.
See List of public DNS servers if you need some ideas, which public free DNS server you could use.
You can specify multiple upstream groups (additional to the default
group) to use different upstream servers for different clients, based on client name (see Client name lookup), client IP address or client subnet (as CIDR).
Tip
You can use *
as wildcard for the sequence of any character or [0-9]
as number range
Example
upstreams:
groups:
default:
- 5.9.164.112
- 1.1.1.1
- tcp-tls:fdns1.dismail.de:853
- https://dns.digitale-gesellschaft.ch/dns-query
laptop*:
- 123.123.123.123
10.43.8.67/28:
- 1.1.1.1
- 9.9.9.9
The above example results in:
123.123.123.123
as the only upstream DNS resolver for clients with a name starting with "laptop"1.1.1.1
and9.9.9.9
for all clients in the subnet10.43.8.67/28
- 4 resolvers (default) for all others clients.
The logic determining what group a client belongs to follows a strict order: IP, client name, CIDR
If a client matches multiple client name or CIDR groups, a warning is logged and the first found group is used.
Upstream strategy
Blocky supports different upstream strategies (default parallel_best
) that determine how and to which upstream DNS servers requests are forwarded.
Currently available strategies:
parallel_best
: blocky picks 2 random (weighted) resolvers from the upstream group for each query and returns the answer from the fastest one. If an upstream failed to answer within the last hour, it is less likely to be chosen for the race.
This improves your network speed and increases your privacy - your DNS traffic will be distributed over multiple providers
(When using 10 upstream servers, each upstream will get on average 20% of the DNS requests)strict
: blocky forwards the request in a strict order. If the first upstream does not respond, the second is asked, and so on.
Example
upstreams:
strategy: strict
groups:
default:
- 1.2.3.4
- 9.8.7.6
Upstream lookup timeout
Blocky will wait 2 seconds (default value) for the response from the external upstream DNS server. You can change this
value by setting the timeout
configuration parameter (in duration format).
Example
upstreams:
timeout: 5s
groups:
default:
- 46.182.19.48
- 80.241.218.68
Bootstrap DNS configuration
These DNS servers are used to resolve upstream DoH and DoT servers that are specified as host names, and list domains. It is useful if no system DNS resolver is configured, and/or to encrypt the bootstrap queries.
Parameter | Type | Mandatory | Default value | Description |
---|---|---|---|---|
upstream | Upstream (see above) | no | ||
ips | List of IPs | yes, if upstream is DoT/DoH | Only valid if upstream is DoH or DoT |
When using an upstream specified by IP, and not by hostname, you can write only the upstream and skip ips
.
Note
Works only on Linux/*nix OS due to golang limitations under Windows.
Example
bootstrapDns:
- upstream: tcp-tls:dns.example.com
ips:
- 123.123.123.123
- upstream: https://234.234.234.234/dns-query
Filtering
Under certain circumstances, it may be useful to filter some types of DNS queries. You can define one or more DNS query types, all queries with these types will be dropped (empty answer will be returned).
Example
filtering:
queryTypes:
- AAAA
This configuration will drop all 'AAAA' (IPv6) queries.
FQDN only
In domain environments, it may be useful to only response to FQDN requests. If this option is enabled blocky respond immediately with NXDOMAIN if the request is not a valid FQDN. The request is therefore not further processed by other options like custom or conditional. Please be aware that by enabling it your hostname resolution will break unless every hostname is part of a domain.
Example
fqdnOnly:
enable: true
Custom DNS
You can define your own domain name to IP mappings. For example, you can use a user-friendly name for a network printer or define a domain name for your local device on order to use the HTTPS certificate. Multiple IP addresses for one domain must be separated by a comma.
Parameter | Type | Mandatory | Default value |
---|---|---|---|
customTTL | duration (no unit is minutes) | no | 1h |
rewrite | string: string (domain: domain) | no | |
mapping | string: string (hostname: address list) | no | |
filterUnmappedTypes | boolean | no | true |
Example
customDNS:
customTTL: 1h
filterUnmappedTypes: true
rewrite:
home: lan
replace-me.com: with-this.com
mapping:
printer.lan: 192.168.178.3
otherdevice.lan: 192.168.178.15,2001:0db8:85a3:08d3:1319:8a2e:0370:7344
This configuration will also resolve any subdomain of the defined domain. For example a query "printer.lan" or " my.printer.lan" will return 192.168.178.3 as IP address.
With the optional parameter rewrite
you can replace domain part of the query with the defined part before the
resolver lookup is performed.
The query "printer.home" will be rewritten to "printer.lan" and return 192.168.178.3.
With parameter filterUnmappedTypes = true
(default), blocky will filter all queries with unmapped types, for example:
AAAA for "printer.lan" or TXT for "otherdevice.lan".
With filterUnmappedTypes = false
a query AAAA "printer.lan" will be forwarded to the upstream DNS server.
Conditional DNS resolution
You can define, which DNS resolver(s) should be used for queries for the particular domain (with all subdomains). This is for example useful, if you want to reach devices in your local network by the name. Since only your router know which hostname belongs to which IP address, all DNS queries for the local network should be redirected to the router.
The optional parameter rewrite
behaves the same as with custom DNS.
The optional parameter fallbackUpstream
, if false (default), return empty result if after rewrite, the mapped resolver returned an empty answer. If true, the original query will be sent to the upstream resolver.
Usage: One usecase when having split DNS for internal and external (internet facing) users, but not all subdomains are listed in the internal domain
Example
conditional:
fallbackUpstream: false
rewrite:
example.com: fritz.box
replace-me.com: with-this.com
mapping:
fritz.box: 192.168.178.1
lan.net: 192.170.1.2,192.170.1.3
# for reverse DNS lookups of local devices
178.168.192.in-addr.arpa: 192.168.178.1
# for all unqualified hostnames
.: 168.168.0.1
Tip
You can use .
as wildcard for all non full qualified domains (domains without dot)
In this example, a DNS query "client.fritz.box" will be redirected to the router's DNS server at 192.168.178.1 and client.lan.net to 192.170.1.2 and 192.170.1.3. The query "client.example.com" will be rewritten to "client.fritz.box" and also redirected to the resolver at 192.168.178.1.
If not found and if fallbackUpstream
was set to true
, the original query "blog.example.com" will be sent upstream.
All unqualified host names (e.g. "test") will be redirected to the DNS server at 168.168.0.1.
One usecase for fallbackUpstream
is when having split DNS for internal and external (internet facing) users, but not all subdomains are listed in the internal domain.
Client name lookup
Blocky can try to resolve a user-friendly client name from the IP address or server URL (DoT and DoH). This is useful for defining of blocking groups, since IP address can change dynamically.
Resolving client name from URL/Host
If DoT or DoH is enabled, you can use a subdomain prefixed with id-
to provide a client name (wildcard ssl certificate
recommended).
Example: domain example.com
DoT Host: id-bob.example.com
-> request's client name is bob
DoH URL: https://id-bob.example.com/dns-query
-> request's client name is bob
For DoH you can also pass the client name as url parameter:
DoH URL: https://blocky.example.com/dns-query/alice
-> request's client name is alice
Resolving client name from IP address
Blocky uses rDNS to retrieve client's name. To use this feature, you can configure a DNS server for client lookup ( typically your router). You can also define client names manually per IP address.
Single name order
Some routers return multiple names for the client (host name and user defined name). With
parameter clientLookup.singleNameOrder
you can specify, which of retrieved names should be used.
Custom client name mapping
You can also map a particular client name to one (or more) IP (ipv4/ipv6) addresses. Parameter clientLookup.clients
contains a map of client name and multiple IP addresses.
Example
clientLookup:
upstream: 192.168.178.1
singleNameOrder:
- 2
- 1
clients:
laptop:
- 192.168.178.29
Use 192.168.178.1
for rDNS lookup. Take second name if present, if not take first name. IP address 192.168.178.29
is mapped to laptop
as client name.
Blocking and whitelisting
Blocky can use lists of domains and IPs to block (e.g. advertisement, malware, trackers, adult sites). You can group several list sources together and define the blocking behavior per client. Blocking uses the DNS sinkhole approach. For each DNS query, the domain name from the request, IP address from the response, and any CNAME records will be checked to determine whether to block the query or not.
To avoid over-blocking, you can use whitelists.
Definition black and whitelists
Lists are defined in groups. This allows using different sets of lists for different clients.
Each list in a group is a "source" and can be downloaded, read from a file, or inlined in the config. See Sources for details and configuring how those are loaded and reloaded/refreshed.
The supported list formats are:
- the well-known Hosts format
- one domain per line (plain domain list)
- one regex per line
Example
blocking:
blackLists:
ads:
- https://s3.amazonaws.com/lists.disconnect.me/simple_ad.txt
- https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts
- |
# inline definition using YAML literal block scalar style
# content is in plain domain list format
someadsdomain.com
anotheradsdomain.com
- |
# inline definition with a regex
/^banners?[_.-]/
special:
- https://raw.githubusercontent.com/StevenBlack/hosts/master/alternates/fakenews/hosts
whiteLists:
ads:
- whitelist.txt
- /path/to/file.txt
- |
# inline definition with YAML literal block scalar style
whitelistdomain.com
In this example you can see 2 groups: ads and special with one list. The ads group includes 2 inline lists.
Warning
If the same group has black and whitelists, whitelists will be used to disable particular blacklist entries. If a group has only whitelist entries -> this means only domains from this list are allowed, all other domains will be blocked.
Warning
You must also define client group mapping, otherwise you black and whitelist definition will have no effect.
Regex support
You can use regex to define patterns to block. A regex entry must start and end with the slash character (/
). Some
Examples:
/baddomain/
will blockwww.baddomain.com
,baddomain.com
, but alsomybaddomain-sometext.com
/^baddomain/
will blockbaddomain.com
, but notwww.baddomain.com
/^apple\.(de|com)$/
will only blockapple.de
andapple.com
Client groups
In this configuration section, you can define, which blocking group(s) should be used for which client in your network. Example: All clients should use the ads group, which blocks advertisement and kids devices should use the adult group, which blocky adult sites.
Clients without an explicit group assignment will use the default group.
You can use the client name (see Client name lookup), client's IP address, client's full-qualified domain name or a client subnet as CIDR notation.
If full-qualified domain name is used (for example "myclient.ddns.org"), blocky will try to resolve the IP address (A and AAAA records) of this domain. If client's IP address matches with the result, the defined group will be used.
Example
blocking:
clientGroupsBlock:
# default will be used, if no special definition for a client name exists
default:
- ads
- special
laptop*:
- ads
192.168.178.1/24:
- special
kid-laptop:
- ads
- adult
All queries from network clients, whose device name starts with laptop
, will be filtered against the ads group's lists. All devices from the subnet 192.168.178.1/24
against the special group and kid-laptop
against ads and adult. All other clients: ads and special.
Tip
You can use *
as wildcard for the sequence of any character or [0-9]
as number range
Block type
You can configure, which response should be sent to the client, if a requested query is blocked (only for A and AAAA queries, NXDOMAIN for other types):
blockType | Example | Description |
---|---|---|
zeroIP | zeroIP | This is the default block type. Server returns 0.0.0.0 (or :: for IPv6) as result for A and AAAA queries |
nxDomain | nxDomain | return NXDOMAIN as return code |
custom IPs | 192.100.100.15, 2001:0db8:85a3:08d3:1319:8a2e:0370:7344 | comma separated list of destination IP addresses. Should contain ipv4 and ipv6 to cover all query types. Useful with running web server on this address to display the "blocked" page. |
Example
blocking:
blockType: nxDomain
Block TTL
TTL for answers to blocked domains can be set to customize the time (in duration format) clients ask for those
domains again. Default Block TTL is 6hours. This setting only makes sense when blockType
is set to nxDomain
or
zeroIP
, and will affect how much time it could take for a client to be able to see the real IP address for a domain
after receiving the custom value.
Example
blocking:
blockType: 192.100.100.15, 2001:0db8:85a3:08d3:1319:8a2e:0370:7344
blockTTL: 10s
Lists Loading
See Sources Loading.
Caching
Each DNS response has a TTL (Time-to-live) value. This value defines, how long is the record valid in seconds. The values are maintained by domain owners, server administrators etc. Blocky caches the answers from all resolved queries in own cache in order to avoid repeated requests. This reduces the DNS traffic and increases the network speed, since blocky can serve the result immediately from the cache.
With following parameters you can tune the caching behavior:
Warning
Wrong values can significantly increase external DNS traffic or memory consumption.
Parameter | Type | Mandatory | Default value | Description |
---|---|---|---|---|
caching.minTime | duration format | no | 0 (use TTL) | How long a response must be cached (min value). If <=0, use response's TTL, if >0 use this value, if TTL is smaller |
caching.maxTime | duration format | no | 0 (use TTL) | How long a response must be cached (max value). If <0, do not cache responses. If 0, use TTL. If > 0, use this value, if TTL is greater |
caching.maxItemsCount | int | no | 0 (unlimited) | Max number of cache entries (responses) to be kept in cache (soft limit). Default (0): unlimited. Useful on systems with limited amount of RAM. |
caching.prefetching | bool | no | false | if true, blocky will preload DNS results for often used queries (default: names queried more than 5 times in a 2 hour time window). Results in cache will be loaded again on their expire (TTL). This improves the response time for often used queries, but significantly increases external traffic. It is recommended to increase "minTime" to reduce the number of prefetch queries to external resolvers. |
caching.prefetchExpires | duration format | no | 2h | Prefetch track time window |
caching.prefetchThreshold | int | no | 5 | Name queries threshold for prefetch |
caching.prefetchMaxItemsCount | int | no | 0 (unlimited) | Max number of domains to be kept in cache for prefetching (soft limit). Default (0): unlimited. Useful on systems with limited amount of RAM. |
caching.cacheTimeNegative | duration format | no | 30m | Time how long negative results (NXDOMAIN response or empty result) are cached. A value of -1 will disable caching for negative results. |
Example
caching:
minTime: 5m
maxTime: 30m
prefetching: true
Redis
Blocky can synchronize its cache and blocking state between multiple instances through redis. Synchronization is disabled if no address is configured.
Parameter | Type | Mandatory | Default value | Description |
---|---|---|---|---|
redis.address | string | no | Server address and port or master name if sentinel is used | |
redis.username | string | no | Username if necessary | |
redis.password | string | no | Password if necessary | |
redis.database | int | no | 0 | Database |
redis.required | bool | no | false | Connection is required for blocky to start |
redis.connectionAttempts | int | no | 3 | Max connection attempts |
redis.connectionCooldown | duration format | no | 1s | Time between the connection attempts |
redis.sentinelUsername | string | no | Sentinel username if necessary | |
redis.sentinelPassword | string | no | Sentinel password if necessary | |
redis.sentinelAddresses | string[] | no | Sentinel host list (Sentinel is activated if addresses are defined) |
Example
redis:
address: redismaster
username: usrname
password: passwd
database: 2
required: true
connectionAttempts: 10
connectionCooldown: 3s
sentinelUsername: sentUsrname
sentinelPassword: sentPasswd
sentinelAddresses:
- redis-sentinel1:26379
- redis-sentinel2:26379
- redis-sentinel3:26379
Prometheus
Blocky can expose various metrics for prometheus. To use the prometheus feature, the HTTP listener must be enabled ( see Basic Configuration).
Parameter | Mandatory | Default value | Description |
---|---|---|---|
prometheus.enable | no | false | If true, enables prometheus metrics |
prometheus.path | no | /metrics | URL path to the metrics endpoint |
Example
prometheus:
enable: true
path: /metrics
Query logging
You can enable the logging of DNS queries (question, answer, client, duration etc.) to a daily CSV file (can be opened in Excel or OpenOffice Calc) or MySQL/MariaDB database.
Warning
Query file/database contains sensitive information. Please ensure to inform users, if you log their queries.
Query log types
You can select one of following query log types:
mysql
- log each query in the external MySQL/MariaDB databasepostgresql
- log each query in the external PostgreSQL databasecsv
- log into CSV file (one per day)csv-client
- log into CSV file (one per day and per client)console
- log into console outputnone
- do not log any queries
Query log fields
You can choose which information from processed DNS request and response should be logged in the target system. You can define one or more of following fields:
clientIP
- origin IP address from the requestclientName
- resolved client name(s) from the origins requestresponseReason
- reason for the response (e.g. from which upstream resolver), response type and coderesponseAnswer
- returned DNS answerquestion
- DNS question from the requestduration
- request processing time in milliseconds
Hint
If not defined, blocky will log all available information
Configuration parameters:
Parameter | Type | Mandatory | Default value | Description |
---|---|---|---|---|
queryLog.type | enum (mysql, postgresql, csv, csv-client, console, none (see above)) | no | Type of logging target. Console if empty | |
queryLog.target | string | no | directory for writing the logs (for csv) or database url (for mysql or postgresql) | |
queryLog.logRetentionDays | int | no | 0 | if > 0, deletes log files/database entries which are older than ... days |
queryLog.creationAttempts | int | no | 3 | Max attempts to create specific query log writer |
queryLog.CreationCooldown | duration format | no | 2 | Time between the creation attempts |
queryLog.fields | list enum (clientIP, clientName, responseReason, responseAnswer, question, duration) | no | all | which information should be logged |
Hint
Please ensure, that the log directory is writable or database exists. If you use docker, please ensure, that the directory is properly mounted (e.g. volume)
example for CSV format with limited logging information
Example
queryLog:
type: csv
target: /logs
logRetentionDays: 7
fields:
- clientIP
- duration
example for Database
Example
queryLog:
type: mysql
target: db_user:db_password@tcp(db_host_or_ip:3306)/db_user?charset=utf8mb4&parseTime=True&loc=Local
logRetentionDays: 7
Hosts file
You can enable resolving of entries, located in local hosts file.
Configuration parameters:
Parameter | Type | Mandatory | Default value | Description |
---|---|---|---|---|
hostsFile.filePath | string | no | Path to hosts file (e.g. /etc/hosts on Linux) | |
hostsFile.hostsTTL | duration (no units is minutes) | no | 1h | TTL |
hostsFile.refreshPeriod | duration format | no | 1h | Time between hosts file refresh |
hostsFile.filterLoopback | bool | no | false | Filter loopback addresses (127.0.0.0/8 and ::1) |
Example
hostsFile:
filePath: /etc/hosts
hostsTTL: 1h
refreshPeriod: 30m
Deliver EDE codes as EDNS0 option
DNS responses can be extended with EDE codes according to RFC8914.
Configuration parameters:
Parameter | Type | Mandatory | Default value | Description |
---|---|---|---|---|
ede.enable | bool | no | false | If true, DNS responses are deliverd with EDE codes |
Example
ede:
enable: true
Special Use Domain Names
SUDN (Special Use Domain Names) are always enabled as they are required by various RFCs.
Some RFCs have optional recommendations, which are configurable as described below.
Configuration parameters:
Parameter | Type | Mandatory | Default value | Description |
---|---|---|---|---|
specialUseDomains.rfc6762-appendixG | bool | no | true | Block TLDs listed in RFC 6762 Appendix G |
Example
specialUseDomains:
rfc6762-appendixG: true
SSL certificate configuration (DoH / TLS listener)
See Wiki - Configuration of HTTPS for detailed information, how to create and configure SSL certificates.
DoH url: https://host:port/dns-query
Sources
Sources are a concept shared by the blocking and hosts file resolvers. They represent where to load the files for each resolver.
The supported source types are:
- HTTP(S) URL (any source starting with
http
) - inline configuration (any source containing a newline)
- local file path (any source not matching the above rules)
Note
The format/content of the sources depends on the context: lists and hosts files have different, but overlapping, supported formats.
Example
- https://example.com/a/source # blocky will download and parse the file
- /a/file/path # blocky will read the local file
- | # blocky will parse the content of this multi-line string
# inline configuration
Sources Loading
This sections covers loading
configuration that applies to both the blocking and hosts file resolvers.
These settings apply only to the resolver under which they are nested.
Example
blocking:
loading:
# only applies to white/blacklists
hostsFile:
loading:
# only applies to hostsFile sources
Refresh / Reload
To keep source contents up-to-date, blocky can periodically refresh and reparse them. Default period is **
4 hours. You can configure this by setting the refreshPeriod
parameter to a value in duration format**.
A value of zero or less will disable this feature.
Example
loading:
refreshPeriod: 1h
Refresh every hour.
Downloads
Configures how HTTP(S) sources are downloaded:
Parameter | Type | Mandatory | Default value | Description |
---|---|---|---|---|
timeout | duration | no | 5s | Download attempt timeout |
attempts | int | no | 3 | How many download attempts should be performed |
cooldown | duration | no | 500ms | Time between the download attempts |
Example
loading:
downloads:
timeout: 4m
attempts: 5
cooldown: 10s
Strategy
This configures how Blocky startup works.
The default strategy is blocking.
strategy | Description |
---|---|
blocking | all sources are loaded before DNS resolution starts |
failOnError | like blocking but blocky will shut down if any source fails to load |
fast | blocky starts serving DNS immediately and sources are loaded asynchronously. The features requiring the sources should enable soon after |
Example
loading:
strategy: failOnError
Max Errors per Source
Number of errors allowed when parsing a source before it is considered invalid and parsing stops.
A value of -1 disables the limit.
Example
loading:
maxErrorsPerSource: 10
Concurrency
Blocky downloads and processes sources concurrently. This allows limiting how many can be processed in the same time.
Larger values can reduce the overall list refresh time at the cost of using more RAM. Please consider reducing this value on systems with limited memory.
Default value is 4.
Example
loading:
concurrency: 10
Note
As with other settings under loading
, the limit applies to the blocking and hosts file resolvers separately.
The total number of concurrent sources concurrently processed can reach the sum of both values.
For example if blocking has a limit set to 8 and hosts file's is 4, there could be up to 12 concurrent jobs.