ALOHA Documentation 12.5

Configuring Transport Layer Security (TLS)

You configure TLS settings in HAProxy Enterprise in the global section, the frontend, and the backend.

Define TLS settings in the Global Section

Directive	Description
`ssl-default-bind-ciphers <ciphers>`	A string describing the list of cipher suite algorithms that HAProxy supports. It applies to all `bind` lines where SSL is enabled Note Mozilla offers a page of TLS recommended configurations for modern, intermediate, and old backward compatibility ciphers here: You can copy and paste the one to suit your needs.
`ssl-default-bind-options [<option>]...`	SSL/TLS options to apply to all `bind` lines where SSL is enabled. `<options>` are the ones from the frontend bind directive
`ssl-default-server-ciphers <ciphers>`	A string describing the list of cipher suite algorithms. It applies to all servers where SSL is enabled Note Mozilla offers a page of TLS recommended configurations for modern, intermediate, and old backward compatibility ciphers here: You can copy and paste the one to suit your needs.
`ssl-default-server-options [<option>]...`	SSL/TLS options to apply to all `bind` lines where SSL is enabled. `<options>` are the one from the backend server directive
`ssl-server-verify [none\|required]`	Default behavior for TLS connection verification on the server side: When set to `none`, certificate errors are ignored. The default is `required`, which means that HAProxy refuses the connection to a server if its certificate is in error (self-signed, outdated, etc...).
`tune.ssl.cachesize <number>`	Sets the size of the global SSL/TLS session cache. Default number is `20000`. When the cache is full and a new entry is required, the least recently used entry is removed.
`tune.ssl.lifetime <timeout>`	Sets the life time of a SSL/TLS session in the cache. `timeout` is expressed in seconds, and its default value is 300 (5 minutes). After timeout, the session is purged from the cache and a new one is generated.
`tune.ssl.maxrecord <number>`	Sets the maximum `<number>` of bytes passed to the SSL/TLS layer at a time. By default, `<number>` is 0, which means no limit. The client cannot start deciphering the stream until it has received a full segment. Reducing this value may improve application response time on the client side.
`tune.ssl.default-dh-param <number>`	Sets the maximum size of the Diffie-Hellman parameters used to generate the ephemeral/temporary Diffie-Hellman key when using DHE key exchange. Default `<number>` value is `1024`. Higher values increase CPU load and may not be supported by some clients (IE:Java 7).

Define bind directives on the frontend

The following directives are valid only if the bind line also owns the statement ssl:

Directive	Description
`alpn <protocols>`	Enables the TLS ALPN extension and advertises the `<protocol>` list (comma separated) supported by HAProxy itself and/or the server behind it.
`ca-file <ca-file>`	Designates the CA certificate to use in order to validate CA certificates provided by clients.
`ca-ignore-err all\|<errorid>,...`	Sets a list of TLS error IDs to ignore when performing TLS handshakes at depth > 0. The TLS handshake is aborted when an error occurs. By default, no errors are ignored. When `all` is set, all errors are ignored. Note The SSL handshake is ignored when an error occurs.
`ciphers`	A string describing the list of cipher suite algorithms Note Mozilla offers a page of TLS recommended configurations for modern, intermediate, and old backward compatibility ciphers here: You can copy and paste the ones that suit your needs.
`crl-file <crlfile>`	Designates a PEM file (Privacy Enhanced Mail) from which HAProxy can load a certificate revocation list. The list is used to verify client certificates.
`crt <pem-file>`	Designates the file containing the certificate and its associated private key. Possibly, intermediaries and root certificates may be included as well. The `<pem-file>` format is PEM. After multiple `crt <pem-file>` certificates are loaded, HAProxy uses the SNI from the client to choose the best one. If there is no SNI, then HAProxy loads the default certificate, which is the first on the list.
`crt-ignore-err all\|<errorid>,...`	Sets a list of TLS error IDs to ignore during verification at depth 0. `<errors>` is a comma separated list. By default, no error is ignored. When `all` is used, all errors are ignored. Note The SSL handshake is ignored when an error occurs.
`crt-list <file> [[!]<snifilter ...]`	Designates a file containing a list of PEM file certificates and associated optional list of SNI filters. Each line in `<file>` follows this scheme: `<pemfile> [[!]<snifilter> ...]` The SNI filter supports wildcards. Negative filters are also supported, but they are only useful when combined with a wildcard filter to exclude a specific SNI.
`force-sslv3`	Enforces the use of SSL protocol version SSLv3. Note Not recommended on Internet because of the poodle vulnerability: https://en.m.wikipedia.org/wiki/POODLE
`force-tlsv10`	Enforces the use of TLS protocol version 1.0
`force-tlsv11`	Enforces the use of TLS protocol version 1.1
`force-tlsv12`	Enforces the use of TLS protocol version 1.2
`no-sslv3`	Disables support of SSLv3 protocol
`no-tls-tickets`	Disables support of TLS tickets, used to resume TLS sessions with compatible clients
`no-tlsv10`	Disables support of TLS 1.0 protocol
`no-tlsv11`	Disables support of TLS 1.1 protocol
`no-tlsv12`	Disables support of TLS 1.2 protocol
`ssl`	Enables a TLS/SSL endpoint on this listener in order to cipher/decipher the traffic.
`strict-sni`	The SSL/TLS negotiation is allowed only if the client provides a SNI that matches a certificate loaded by HAProxy. The default certificate is ignored in this case.
`verify [none\|optional\|required]`	Sets HAProxy's behavior regarding client side certificate: `none` (default value) : client certificate is not requested. `optional`: HAProxy requests a client certificate, and the TLS handshake is successful even if the client doesn't provide one. `required`: HAProxy requests a client certificate, but the TLS handshake is aborted if the client doesn't provide one.

Define server directive settings on the backend

Directive	Description
`ca-file <ca-file>`	Designates the CA certificate to use to validate certificates provided by servers
`ciphers`	A string describing the list of cipher suite algorithms to use to get connected to the servers Note Mozilla offers a page of TLS recommended configurations for modern, intermediate, and old backward compatibility ciphers here: You can copy and paste the ones that suit your needs.
`crl-file <crlfile>`	Designates a PEM file from which HAProxy can load a certificate revocation list. The list is used to verify certificates provided by servers.
`crt <pem-file>`	Designates the file containing a client certificate and its associated private key. HAProxy will use it if the server asks for a client certificate.
`force-sslv3`	Enforces the use of SSL protocol version SSLv3. Note Not recommended on Internet because of the poodle vulnerability: https://en.m.wikipedia.org/wiki/POODLE
`force-tlsv10`	Enforces the use of TLS protocol version 1.0
`force-tlsv11`	Enforces the use of TLS protocol version 1.1
`force-tlsv12`	Enforces the use of TLS protocol version 1.2
`no-sslv3`	Disables support of SSLv3 protocol
`no-tls-tickets`	Disables support of TLS tickets, used to resume TLS sessions with compatible clients
`no-tlsv10`	Disables support of TLS 1.0 protocol
`no-tlsv11`	Disables support of TLS 1.1 protocol
`no-tlsv12`	Disables support of TLS 1.2 protocol
`sni <sample>`	Evaluates the sample fecth expression and uses the result as a string for the SNI TLS extension sent to the server.
`ssl`	Creates a TLS/SSL socket when connecting to this server to cipher/decipher the traffic
`verify [none\|required]`	Sets HAProxy's behavior regarding the certificated presented by the server: `none`: does not verify the certificate of the server `required` (default value): the TLS handshake is aborted if the validation of the certificate presented by the server returns an error. Note The certificate of the server is validated using the server's `ca-file` and `crl-file` directive.
`veryfyhost <hostname>`	Sets a `<hostname>` to look for in the Subject and SubjectAlternateNames fields in the certificate from the server. If `<hostname>` is not found, then the TLS handshake is aborted. Note This only applies when `verify required` is configured.

Example TLS Configurations

Define Global Settings

The following are examples of settings available in the global section.

Disable SSLv3 everywhere:

global
    ssl-default-bind-options no-sslv3

Set a default cipher list to use:

global
    ssl-default-bind-ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK

Disable validation of certificates presented by servers (because of self-signed certificates):

global
    ssl-server-verify none

Force validation of certificates presented by servers:

global
    ssl-server-verify required

Increase TLS session cache size and lifetime to avoid computing too many symmetric keys:

global
    tune.ssl.cachesize 100000
    tune.ssl.lifetime 600

Set up a TLS record to match a TCP segment size to improve client side rendering of content:

global
    tune.ssl.maxrecord 1460

Define Listener (frontend) Settings

The following are examples of settings available for the listener:

Enable SSL processing on a bind line:

frontend f_myapp
    bind 10.0.0.1:443 ssl crt mycrt

Anounce supported protocols using TLS NPN or ALPN extension:

frontend f_myapp
    bind 10.0.0.1:443 ssl crt mycrt alpn http/1.1,http/1.0

or:

frontend f_myapp
    bind 10.0.0.1:443 ssl crt mycrt npn http/1.1,http/1.0

Enable SSL processing on a bind line and make client certificate mandatory for the connection:

frontend f_myapp
    bind 10.0.0.1:443 ssl crt mycrt ca-file ./ca.crt verify required

Load multiple certificates over a single IP:

frontend f_myapp
    bind 10.0.0.1:443 ssl crt star.mydomain.com crt www.mydomain.net

Note

The first one is used by default when the client does not send any SNI, or the SNI sent does not match any loaded certificate.

Define Server Settings

The following are examples of settings available for the server:

Do not check the validity of a server certificate (can be dangerous):

backend b_myapp
    # ...
    server app1 10.0.0.1:443 ssl verify none

Use a company's internal CA to check a server certificate; also check the ssl-server-verify global option to force validation over all servers by default.

backend b_myapp
    # ...
    server app1 10.0.0.1:443 ssl verify required ca-file /etc/haproxy/myca.pem

Use a client certificate to get connected on a server; also check the ssl-server-verify global option to force validation over all servers by default.

backend b_myapp
    # ...
    server app1 10.0.0.1:443 ssl verify required ca-file /etc/haproxy/myca.pem crt /etc/haproxy/client.pem

Use the host header as SNI when opening a TLS connection on to a server:

backend b_myapp
    mode http
    # ...
    server app1 10.0.0.1:443 ssl sni req.hdr(Host)

Next up

Capturing Traffic Data