ACME (Let's Encrypt) Configuration

See Let's Encrypt examples and Docker & Let's Encrypt user guide as well.

Configuration

# Sample entrypoint configuration when using ACME.
[entryPoints]
  [entryPoints.http]
  address = ":80"
  [entryPoints.https]
  address = ":443"
    [entryPoints.https.tls]

# Enable ACME (Let's Encrypt): automatic SSL.
[acme]
# Email address used for registration.
#
# Required
#
email = "[email protected]"
# File used for certificates storage.
#
# Optional (Deprecated)
#
#storageFile = "acme.json"
# File or key used for certificates storage.
#
# Required
#
storage = "acme.json"
# or `storage = "traefik/acme/account"` if using KV store.
# Entrypoint to proxy acme apply certificates to.
#
# Required
#
entryPoint = "https"
# Deprecated, replaced by [acme.dnsChallenge].
#
# Optional.
#
# dnsProvider = "digitalocean"
# Deprecated, replaced by [acme.dnsChallenge.delayBeforeCheck].
#
# Optional
# Default: 0
#
# delayDontCheckDNS = 0
# If true, display debug log messages from the acme client library.
#
# Optional
# Default: false
#
# acmeLogging = true
# If true, override certificates in key-value store when using storeconfig.
#
# Optional
# Default: false
#
# overrideCertificates = true
# Deprecated. Enable on demand certificate generation.
#
# Optional
# Default: false
#
# onDemand = true
# Enable certificate generation on frontends host rules.
#
# Optional
# Default: false
#
# onHostRule = true
# CA server to use.
# Uncomment the line to use Let's Encrypt's staging server,
# leave commented to go to prod.
#
# Optional
# Default: "https://acme-v02.api.letsencrypt.org/directory"
#
# caServer = "https://acme-staging-v02.api.letsencrypt.org/directory"
# KeyType to use.
#
# Optional
# Default: "RSA4096"
#
# Available values : "EC256", "EC384", "RSA2048", "RSA4096", "RSA8192"
#
# KeyType = "RSA4096"
# Use a TLS-ALPN-01 ACME challenge.
#
# Optional (but recommended)
#
[acme.tlsChallenge]
# Use a HTTP-01 ACME challenge.
#
# Optional
#
# [acme.httpChallenge]
  # EntryPoint to use for the HTTP-01 challenges.
  #
  # Required
  #
  # entryPoint = "http"
# Use a DNS-01 ACME challenge rather than HTTP-01 challenge.
# Note: mandatory for wildcard certificate generation.
#
# Optional
#
# [acme.dnsChallenge]
  # DNS provider used.
  #
  # Required
  #
  # provider = "digitalocean"
  # By default, the provider will verify the TXT DNS challenge record before letting ACME verify.
  # If delayBeforeCheck is greater than zero, this check is delayed for the configured duration in seconds.
  # Useful if internal networks block external DNS queries.
  #
  # Optional
  # Default: 0
  #
  # delayBeforeCheck = 0
  # Use following DNS servers to resolve the FQDN authority.
  #
  # Optional
  # Default: empty
  #
  # resolvers = ["1.1.1.1:53", "8.8.8.8:53"]
  # Disable the DNS propagation checks before notifying ACME that the DNS challenge is ready.
  #
  # NOT RECOMMENDED:
  # Increase the risk of reaching Let's Encrypt's rate limits.
  #
  # Optional
  # Default: false
  #
  # disablePropagationCheck = true
# Domains list.
# Only domains defined here can generate wildcard certificates.
# The certificates for these domains are negotiated at traefik startup only.
#
# [[acme.domains]]
#   main = "local1.com"
#   sans = ["test1.local1.com", "test2.local1.com"]
# [[acme.domains]]
#   main = "local2.com"
# [[acme.domains]]
#   main = "*.local3.com"
#   sans = ["local3.com", "test1.test1.local3.com"]

caServer

The CA server to use.

This example shows the usage of Let's Encrypt's staging server:

[acme]
# ...
caServer = "https://acme-staging-v02.api.letsencrypt.org/directory"
# ...

ACME Challenge

tlsChallenge

Use the TLS-ALPN-01 challenge to generate and renew ACME certificates by provisioning a TLS certificate.

[acme]
# ...
entryPoint = "https"
[acme.tlsChallenge]

Note

If the TLS-ALPN-01 challenge is used, acme.entryPoint has to be reachable by Let's Encrypt through port 443. This is a Let's Encrypt limitation as described on the community forum.

httpChallenge

Use the HTTP-01 challenge to generate and renew ACME certificates by provisioning a HTTP resource under a well-known URI.

Redirection is fully compatible with the HTTP-01 challenge.

[acme]
# ...
entryPoint = "https"
[acme.httpChallenge]
  entryPoint = "http"

Note

If the HTTP-01 challenge is used, acme.httpChallenge.entryPoint has to be defined and reachable by Let's Encrypt through port 80. This is a Let's Encrypt limitation as described on the community forum.

entryPoint

Specify the entryPoint to use during the challenges.

defaultEntryPoints = ["http", "https"]
[entryPoints]
  [entryPoints.http]
  address = ":80"
  [entryPoints.https]
  address = ":443"
    [entryPoints.https.tls]
# ...
[acme]
  # ...
  entryPoint = "https"
  [acme.httpChallenge]
    entryPoint = "http"

Note

acme.httpChallenge.entryPoint has to be reachable through port 80. It's a Let's Encrypt limitation as described on the community forum.

dnsChallenge

Use the DNS-01 challenge to generate and renew ACME certificates by provisioning a DNS record.

[acme]
# ...
[acme.dnsChallenge]
  provider = "digitalocean"
  delayBeforeCheck = 0
# ...

delayBeforeCheck

By default, the provider will verify the TXT DNS challenge record before letting ACME verify. If delayBeforeCheck is greater than zero, this check is delayed for the configured duration in seconds.

Useful if internal networks block external DNS queries.

Note

A provider is mandatory.

provider

Here is a list of supported providers, that can automate the DNS verification, along with the required environment variables and their wildcard & root domain support for each. Do not hesitate to complete it. Every lego environment variable can be overridden by their respective _FILE counterpart, which should have a filepath to a file that contains the secret as its value. For example, CF_API_EMAIL_FILE=/run/secrets/traefik_cf-api-email could be used to provide a Cloudflare API email address as a Docker secret named traefik_cf-api-email.

• (1): more information about the HTTP message format can be found here
• (2): https://cloud.google.com/docs/authentication/production#providing_credentials_to_your_application
• (3): https://github.com/golang/oauth2/blob/36a7019397c4c86cf59eeab3bc0d188bac444277/google/default.go#L61-L76

resolvers

Use custom DNS servers to resolve the FQDN authority.

[acme]
# ...
[acme.dnsChallenge]
  # ...
  resolvers = ["1.1.1.1:53", "8.8.8.8:53"]

domains

You can provide SANs (alternative domains) to each main domain. All domains must have A/AAAA records pointing to Traefik. Each domain & SAN will lead to a certificate request.

Note

The certificates for the domains listed in acme.domains are negotiated at traefik startup only.

[acme]
# ...
[[acme.domains]]
  main = "local1.com"
  sans = ["test1.local1.com", "test2.local1.com"]
[[acme.domains]]
  main = "local2.com"
[[acme.domains]]
  main = "*.local3.com"
  sans = ["local3.com", "test1.test1.local3.com"]
# ...

Warning

Take note that Let's Encrypt applies rate limiting.

Note

Wildcard certificates can only be verified through a DNS-01 challenge.

Wildcard Domains

ACME V2 allows wildcard certificate support. As described in Let's Encrypt's post wildcard certificates can only be generated through a DNS-01 challenge.

[acme]
# ...
[[acme.domains]]
  main = "*.local1.com"
  sans = ["local1.com"]
# ...

It is not possible to request a double wildcard certificate for a domain (for example *.*.local.com). Most likely the root domain should receive a certificate too, so it needs to be specified as SAN and 2 DNS-01 challenges are executed. In this case the generated DNS TXT record for both domains is the same. Even though this behaviour is DNS RFC compliant, it can lead to problems as all DNS providers keep DNS records cached for a certain time (TTL) and this TTL can be superior to the challenge timeout making the DNS-01 challenge fail. The Traefik ACME client library LEGO supports some but not all DNS providers to work around this issue. The provider table indicates if they allow generating certificates for a wildcard domain and its root domain.

onDemand (Deprecated)

DEPRECATED

This option is deprecated.

[acme]
# ...
onDemand = true
# ...

Enable on demand certificate generation.

This will request certificates from Let's Encrypt during the first TLS handshake for host names that do not yet have certificates.

Warning

TLS handshakes are slow when requesting a host name certificate for the first time. This can lead to DoS attacks!

Warning

Take note that Let's Encrypt applies rate limiting.

onHostRule

[acme]
# ...
onHostRule = true
# ...

Enable certificate generation on frontend Host rules (for frontends wired to the acme.entryPoint).

This will request a certificate from Let's Encrypt for each frontend with a Host rule.

For example, the rule Host:test1.traefik.io,test2.traefik.io will request a certificate with main domain test1.traefik.io and SAN test2.traefik.io.

Warning

onHostRule option can not be used to generate wildcard certificates. Refer to wildcard generation for further information.

storage

The storage option sets the location where your ACME certificates are saved to.

[acme]
# ...
storage = "acme.json"
# ...

The value can refer to two kinds of storage:

• a JSON file
• a KV store entry

DEPRECATED

storage replaces storageFile which is deprecated.

Note

During migration to a KV store use both storageFile and storage to migrate ACME certificates too. See storeconfig subcommand for further information.

As a File

ACME certificates can be stored in a JSON file that needs to have file mode 600.

In Docker you can either mount the JSON file or the folder containing it:

docker run -v "/my/host/acme.json:acme.json" traefik

docker run -v "/my/host/acme:/etc/traefik/acme" traefik

Warning

This file cannot be shared across multiple instances of Traefik at the same time. Please use a KV Store entry instead.

As a Key Value Store Entry

ACME certificates can be stored in a KV Store entry. This kind of storage is mandatory in cluster mode.

storage = "traefik/acme/account"

Because KV stores (like Consul) have limited entry size the certificates list is compressed before it is saved as KV store entry.

Note

It is possible to store up to approximately 100 ACME certificates in Consul.

ACME v2 Migration

During migration from ACME v1 to ACME v2, using a storage file, a backup of the original file is created in the same place as the latter (with a .bak extension).

For example: if acme.storage's value is /etc/traefik/acme/acme.json, the backup file will be /etc/traefik/acme/acme.json.bak.

Note

When Traefik is launched in a container, the storage file's parent directory needs to be mounted to be able to access the backup file on the host. Otherwise the backup file will be deleted when the container is stopped. Traefik will only generate it once!

dnsProvider (Deprecated)

DEPRECATED

This option is deprecated. Please use dnsChallenge.provider instead.

delayDontCheckDNS (Deprecated)

DEPRECATED

This option is deprecated. Please use dnsChallenge.delayBeforeCheck instead.

Fallbacks

If Let's Encrypt is not reachable, these certificates will be used:

• ACME certificates already generated before downtime
• Expired ACME certificates
• Provided certificates

Note

For new (sub)domains which need Let's Encrypt authentification, the default Traefik certificate will be used until Traefik is restarted.