Application Gateway TLS policy overview

You can use Azure Application Gateway to centralize TLS/SSL certificate management and reduce encryption and decryption overhead from a back-end server farm. This centralized TLS handling also lets you specify a central TLS policy that's suited to your organizational security requirements. This helps you meet compliance requirements as well as security guidelines and recommended practices.

The TLS policy includes control of the TLS protocol version as well as the cipher suites and the order in which ciphers are used during a TLS handshake. Application Gateway offers two mechanisms for controlling TLS policy. You can use either a predefined policy or a custom policy.

Predefined TLS policy

Application Gateway has three predefined security policies. You can configure your gateway with any of these policies to get the appropriate level of security. The policy names are annotated by the year and month in which they were configured. Each policy offers different TLS protocol versions and cipher suites. We recommend that you use the newest TLS policies to ensure the best TLS security.

Known issue

Application Gateway v2 does not support the following DHE ciphers and these won't be used for the TLS connections with clients even though they are mentioned in the predefined policies. Instead of DHE ciphers, secure and faster ECDHE ciphers are recommended.

  • TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
  • TLS_DHE_RSA_WITH_AES_128_CBC_SHA
  • TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
  • TLS_DHE_RSA_WITH_AES_256_CBC_SHA
  • TLS_DHE_DSS_WITH_AES_128_CBC_SHA256
  • TLS_DHE_DSS_WITH_AES_128_CBC_SHA
  • TLS_DHE_DSS_WITH_AES_256_CBC_SHA256
  • TLS_DHE_DSS_WITH_AES_256_CBC_SHA

AppGwSslPolicy20150501

Property Value
Name AppGwSslPolicy20150501
MinProtocolVersion TLSv1_0
Default True (if no predefined policy is specified)
CipherSuites TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
TLS_DHE_RSA_WITH_AES_256_CBC_SHA
TLS_DHE_RSA_WITH_AES_128_CBC_SHA
TLS_RSA_WITH_AES_256_GCM_SHA384
TLS_RSA_WITH_AES_128_GCM_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA256
TLS_RSA_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_DHE_DSS_WITH_AES_256_CBC_SHA256
TLS_DHE_DSS_WITH_AES_128_CBC_SHA256
TLS_DHE_DSS_WITH_AES_256_CBC_SHA
TLS_DHE_DSS_WITH_AES_128_CBC_SHA
TLS_RSA_WITH_3DES_EDE_CBC_SHA
TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA

AppGwSslPolicy20170401

Property Value
Name AppGwSslPolicy20170401
MinProtocolVersion TLSv1_1
Default False
CipherSuites TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_256_GCM_SHA384
TLS_RSA_WITH_AES_128_GCM_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA256
TLS_RSA_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA

AppGwSslPolicy20170401S

Property Value
Name AppGwSslPolicy20170401S
MinProtocolVersion TLSv1_2
Default False
CipherSuites TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_256_GCM_SHA384
TLS_RSA_WITH_AES_128_GCM_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA256
TLS_RSA_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA

Custom TLS policy

If a predefined TLS policy needs to be configured for your requirements, you must define your own custom TLS policy. With a custom TLS policy, you have complete control over the minimum TLS protocol version to support, as well as the supported cipher suites and their priority order.

Important

If you are using a custom SSL policy in Application Gateway v1 SKU (Standard or WAF), make sure that you add the mandatory cipher "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256" to the list. This cipher is required to enable metrics and logging in the Application Gateway v1 SKU. This is not mandatory for Application Gateway v2 SKU (Standard_v2 or WAF_v2).

TLS/SSL protocol versions

  • SSL 2.0 and 3.0 are disabled by default for all application gateways. These protocol versions are not configurable.
  • A custom TLS policy gives you the option to select any one of the following three protocols as the minimum TLS protocol version for your gateway: TLSv1_0, TLSv1_1, and TLSv1_2.
  • If no TLS policy is defined, all three protocols (TLSv1_0, TLSv1_1, and TLSv1_2) are enabled.

Cipher suites

Application Gateway supports the following cipher suites from which you can choose your custom policy. The ordering of the cipher suites determines the priority order during TLS negotiation.

  • TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
  • TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
  • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
  • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
  • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
  • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
  • TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
  • TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
  • TLS_DHE_RSA_WITH_AES_256_CBC_SHA
  • TLS_DHE_RSA_WITH_AES_128_CBC_SHA
  • TLS_RSA_WITH_AES_256_GCM_SHA384
  • TLS_RSA_WITH_AES_128_GCM_SHA256
  • TLS_RSA_WITH_AES_256_CBC_SHA256
  • TLS_RSA_WITH_AES_128_CBC_SHA256
  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA
  • TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
  • TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
  • TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
  • TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
  • TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
  • TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
  • TLS_DHE_DSS_WITH_AES_256_CBC_SHA256
  • TLS_DHE_DSS_WITH_AES_128_CBC_SHA256
  • TLS_DHE_DSS_WITH_AES_256_CBC_SHA
  • TLS_DHE_DSS_WITH_AES_128_CBC_SHA
  • TLS_RSA_WITH_3DES_EDE_CBC_SHA
  • TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA

Note

TLS cipher suites used for the connection are also based on the type of the certificate being used. In client to application gateway connections, the cipher suites used are based on the type of server certificates on the application gateway listener. In application gateway to backend pool connections, the cipher suites used are based on the type of server certificates on the backend pool servers.

Next steps

If you want to learn to configure a TLS policy, see Configure TLS policy versions and cipher suites on Application Gateway.