traefik/docs/content/reference/routing-configuration/http/middlewares/passtlsclientcert.md

title	description
Traefik PassTLSClientCert Documentation	In Traefik Proxy's HTTP middleware, the PassTLSClientCert adds selected data from passed client TLS certificates to headers. Read the technical documentation.

The passTLSClientCert middleware adds the selected data from the passed client TLS certificate to a header.

Configuration Examples

Pass the pem in the X-Forwarded-Tls-Client-Cert header:

# Pass the pem in the `X-Forwarded-Tls-Client-Cert` header.
http:
  middlewares:
    test-passtlsclientcert:
      passTLSClientCert:
        pem: true

# Pass the pem in the `X-Forwarded-Tls-Client-Cert` header.
[http.middlewares]
  [http.middlewares.test-passtlsclientcert.passTLSClientCert]
    pem = true

# Pass the pem in the `X-Forwarded-Tls-Client-Cert` header.
labels:
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.pem=true"

// Pass the pem in the `X-Forwarded-Tls-Client-Cert` header
{
  "Tags": [
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.pem=true"
  ]
}

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: test-passtlsclientcert
spec:
  passTLSClientCert:
    pem: true

??? example "Pass the pem in the X-Forwarded-Tls-Client-Cert header"

```yaml tab="Structured (YAML)"
# Pass all the available info in the `X-Forwarded-Tls-Client-Cert-Info` header
http:
  middlewares:
    test-passtlsclientcert:
      passTLSClientCert:
        info:
          notAfter: true
          notBefore: true
          sans: true
          subject:
            country: true
            province: true
            locality: true
            organization: true
            organizationalUnit: true
            commonName: true
            serialNumber: true
            domainComponent: true
          issuer:
            country: true
            province: true
            locality: true
            organization: true
            commonName: true
            serialNumber: true
            domainComponent: true
```

```toml tab="Structured (TOML)"
# Pass all the available info in the `X-Forwarded-Tls-Client-Cert-Info` header
[http.middlewares]
  [http.middlewares.test-passtlsclientcert.passTLSClientCert]
    [http.middlewares.test-passtlsclientcert.passTLSClientCert.info]
      notAfter = true
      notBefore = true
      sans = true
      [http.middlewares.test-passtlsclientcert.passTLSClientCert.info.subject]
        country = true
        province = true
        locality = true
        organization = true
        organizationalUnit = true
        commonName = true
        serialNumber = true
        domainComponent = true
      [http.middlewares.test-passtlsclientcert.passTLSClientCert.info.issuer]
        country = true
        province = true
        locality = true
        organization = true
        commonName = true
        serialNumber = true
        domainComponent = true
```

```yaml tab="Labels"
# Pass all the available info in the `X-Forwarded-Tls-Client-Cert-Info` header
labels:
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.notafter=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.notbefore=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.sans=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.serialnumber=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.commonname=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.country=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.domaincomponent=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.locality=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.organization=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.organizationalunit=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.province=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.serialnumber=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.commonname=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.country=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.domaincomponent=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.locality=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.organization=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.province=true"
  - "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.serialnumber=true"
```

```json tab="Tags"
// Pass all the available info in the `X-Forwarded-Tls-Client-Cert-Info` header
{
  //...
  "Tags" : [
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.notafter=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.notbefore=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.sans=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.commonname=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.country=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.domaincomponent=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.locality=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.organization=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.organizationalunit=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.province=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.subject.serialnumber=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.commonname=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.country=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.domaincomponent=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.locality=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.organization=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.province=true",
    "traefik.http.middlewares.test-passtlsclientcert.passtlsclientcert.info.issuer.serialnumber=true"
  ]
}
```

```yaml tab="Kubernetes"
# Pass all the available info in the `X-Forwarded-Tls-Client-Cert-Info` header
apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: test-passtlsclientcert
spec:
  passTLSClientCert:
    info:
      notAfter: true
      notBefore: true
      sans: true
      subject:
        country: true
        province: true
        locality: true
        organization: true
        organizationalUnit: true
        commonName: true
        serialNumber: true
        domainComponent: true
      issuer:
        country: true
        province: true
        locality: true
        organization: true
        commonName: true
        serialNumber: true
        domainComponent: true
```

General Information

passTLSClientCert can add two headers to the request:

• X-Forwarded-Tls-Client-Cert that contains the pem.
• X-Forwarded-Tls-Client-Cert-Info that contains all the selected certificate information in an escaped string.

!!! info

- `X-Forwarded-Tls-Client-Cert-Info` header value is a string that has been escaped in order to be a valid URL query.
- These options only work accordingly to the MutualTLS configuration. i.e, only the certificates that match the `clientAuth.clientAuthType` policy are passed.

Configuration Options

Field	Description	Default	Required
pem	Fills the X-Forwarded-Tls-Client-Cert header with the certificate information. More information here.	false	No
info.serialNumber	Add the Serial Number of the certificate. More information about info here.	false	No
info.notAfter	Add the Not After information from the Validity part. More information about info here.	false	No
info.notBefore	Add the Not Before information from the Validity part. More information about info here.	false	No
info.sans	Add the Subject Alternative Name information from the Subject Alternative Name part. More information about info here.	false	No
info.subject	The info.subject selects the specific client certificate subject details you want to add to the X-Forwarded-Tls-Client-Cert-Info header. More information about info here.	false	No
info.subject.country	Add the country information into the subject. The data is taken from the subject part with the C key. More information about info here.	false	No
info.subject.province	Add the province information into the subject. The data is taken from the subject part with the ST key. More information about info here.	false	No
info.subject.locality	Add the locality information into the subject. The data is taken from the subject part with the L key. More information about info here.	false	No
info.subject.organization	Add the organization information into the subject. The data is taken from the subject part with the O key. More information about info here.	false	No
info.subject.organizationalUnit	Add the organizationalUnit information into the subject. The data is taken from the subject part with the OU key. More information about info here.	false	No
info.subject.commonName	Add the commonName information into the subject. The data is taken from the subject part with the CN key.	false	No
info.subject.serialNumber	Add the serialNumber information into the subject. The data is taken from the subject part with the SN key.	false	No
info.subject.domainComponent	Add the domainComponent information into the subject. The data is taken from the subject part with the DC key. More information about info here.	false	No
info.issuer	The info.issuer selects the specific client certificate issuer details you want to add to the X-Forwarded-Tls-Client-Cert-Info header. More information about info here.	false	No
info.issuer.country	Add the country information into the issuer. The data is taken from the issuer part with the C key. More information about info here.	false	No
info.issuer.province	Add the province information into the issuer. The data is taken from the issuer part with the ST key. More information about info here.	false	No
info.issuer.locality	Add the locality information into the issuer. The data is taken from the issuer part with the L key. More information about info here.	false	No
info.issuer.organization	Add the organization information into the issuer. The data is taken from the issuer part with the O key. More information about info here.	false	No
info.issuer.commonName	Add the commonName information into the issuer. The data is taken from the issuer part with the CN key. More information about info here.	false	No
info.issuer.serialNumber	Add the serialNumber information into the issuer. The data is taken from the issuer part with the SN key. More information about info here.	false	No
info.issuer.domainComponent	Add the domainComponent information into the issuer. The data is taken from the issuer part with the DC key. More information about info here.	false	No

pem

Data Format

The delimiters and \n will be removed.
If there are more than one certificate, they are separated by a ",".

Header size

The X-Forwarded-Tls-Client-Cert header value could exceed the web server header size limit

The header size limit of web servers is commonly between 4kb and 8kb.
If that turns out to be a problem, and if reconfiguring the server to allow larger headers is not an option, one can alleviate the problem by selecting only the interesting parts of the cert, through the use of the info options described below. (And by setting pem to false).

info

The info option selects the specific client certificate details you want to add to the X-Forwarded-Tls-Client-Cert-Info header.

Data Format

The value of the header is an escaped concatenation of all the selected certificate details. Unless specified otherwise, all the header values examples are shown unescaped, for readability.

If there are more than one certificate, they are separated by a ,.

The following example shows such a concatenation, when all the available fields are selected:

Subject="DC=org,DC=cheese,C=FR,C=US,ST=Cheese org state,ST=Cheese com state,L=TOULOUSE,L=LYON,O=Cheese,O=Cheese 2,CN=*.example.com";Issuer="DC=org,DC=cheese,C=FR,C=US,ST=Signing State,ST=Signing State 2,L=TOULOUSE,L=LYON,O=Cheese,O=Cheese 2,CN=Simple Signing CA 2";NB="1747282426";NA="1778818426"SAN="*.example.org,*.example.net,*.example.com,test@example.org,test@example.net,10.0.1.0,10.0.1.2"