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    Server Load Balancer:DescribeLoadBalancerListeners - List SLB listeners

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    Server Load Balancer:DescribeLoadBalancerListeners - List SLB listeners

    Last Updated:Apr 03, 2026

    Queries the listeners of a Classic Load Balancer (CLB) instance.

    Operation description

    Try it now

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    Test

    RAM authorization

    The table below describes the authorization required to call this API. You can define it in a Resource Access Management (RAM) policy. The table's columns are detailed below:

    • Action: The actions can be used in the Action element of RAM permission policy statements to grant permissions to perform the operation.

    • API: The API that you can call to perform the action.

    • Access level: The predefined level of access granted for each API. Valid values: create, list, get, update, and delete.

    • Resource type: The type of the resource that supports authorization to perform the action. It indicates if the action supports resource-level permission. The specified resource must be compatible with the action. Otherwise, the policy will be ineffective.

      • For APIs with resource-level permissions, required resource types are marked with an asterisk (*). Specify the corresponding Alibaba Cloud Resource Name (ARN) in the Resource element of the policy.

      • For APIs without resource-level permissions, it is shown as All Resources. Use an asterisk (*) in the Resource element of the policy.

    • Condition key: The condition keys defined by the service. The key allows for granular control, applying to either actions alone or actions associated with specific resources. In addition to service-specific condition keys, Alibaba Cloud provides a set of common condition keys applicable across all RAM-supported services.

    • Dependent action: The dependent actions required to run the action. To complete the action, the RAM user or the RAM role must have the permissions to perform all dependent actions.

    Action

    Access level

    Resource type

    Condition key

    Dependent action

    slb:DescribeLoadBalancerListeners

    get

    *LoadBalancer

    acs:slb:{#regionId}:{#accountId}:loadbalancer/{#LoadBalancerId}

    None

    None

    Request parameters

    Parameter

    Type

    Required

    Description

    Example

    RegionId

    string

    No

    The ID of the region where the CLB instance is deployed.

    You can call the DescribeRegions operation to query the most recent region list.

    Note

    If the endpoint of the selected region is slb.aliyuncs.com, the RegionId parameter is required.

    cn-hangzhou

    NextToken

    string

    No

    The token that is used for the next query. Valid values:

    • If this is your first query and no subsequent queries are to be sent, ignore this parameter.

    • If a subsequent query is to be sent, set the parameter to the value of NextToken that is returned from the last call.

    FFmyTO70tTpLG6I3FmYAXGKPd****

    MaxResults

    integer

    No

    The number of entries to return in each call.

    Valid values: 1 to 100. If you do not specify this parameter, the default value 20 is used.

    50

    ListenerProtocol

    string

    No

    The protocol used by the listener. Valid values:

    • tcp

    • udp

    • http

    • https

    http

    LoadBalancerId

    array

    No

    The IDs of the CLB instances. You can specify up to 10 instance IDs.

    Note

    If you do not use the SDK to call this operation, use the LoadBalancerId.N parameter.

    lb-123wrwer

    string

    No

    The ID of the CLB instance.

    lb-uf6so8u4g35prnvsw****

    Tag

    array<object>

    No

    The tags.

    object

    No

    The tags.

    Key

    string

    No

    The key of the tag. You can specify up to 20 tag keys. The tag key cannot be an empty string.

    The tag key must be 1 to 64 characters in length and cannot start with aliyun or acs:. It cannot contain http:// or https://.

    TestKey

    Value

    string

    No

    The tag value. Valid values of N: 1 to 20. The tag value can be an empty string.

    The tag value can be up to 128 characters in length and cannot start with aliyun or acs:. The tag value cannot contain http:// or https://.

    TestValue

    ListenerPort

    integer

    No

    The frontend port that is used by the CLB instance.

    443

    Description

    string

    No

    The custom name of the listener.

    HTTPS_443

    Response elements

    Element

    Type

    Description

    Example

    object

    NextToken

    string

    The token that determines the start point of the query. Valid values:

    • If NextToken is empty, it indicates that no subsequent query is to be sent.

    • If a value is returned for NextToken, the value is the token that determines the start point of the next query.

    FFmyTO70tTpLG6I3FmYAXGKPd****

    RequestId

    string

    The ID of the request.

    365F4154-92F6-4AE4-92F8-7FF34B540710

    TotalCount

    integer

    The total number of entries returned.

    10

    MaxResults

    integer

    The number of entries returned per page.

    50

    Listeners

    array<object>

    A list of listeners of the CLB instance.

    Note

    This parameter is not returned if the CLB instance does not have a listener.

    array<object>

    A list of listeners of the CLB instance.

    Note

    This parameter is not returned if the CLB instance does not have a listener.

    AclType

    string

    The type of access control. Valid values:

    • white: The listener forwards requests only from IP addresses and CIDR blocks on the whitelist. Your service may be adversely affected if the whitelist is not properly configured. If a whitelist is configured, the listener forwards requests only from IP addresses that are added to the whitelist.

    If you configure a whitelist but no IP address is added to the whitelist, the listener forwards all requests.

    • black: The listener blocks requests from IP addresses and CIDR blocks on the blacklist.

    If you configure a blacklist but no IP address is added to the blacklist, the listener forwards all requests.

    white

    Status

    string

    The status of the listener. Valid values:

    • running: The listener is running normally.

    • stopped: The listener is stopped.

    running

    VServerGroupId

    string

    The ID of the vServer group associated with the listener.

    rsp-cige6j****

    ListenerProtocol

    string

    The protocol used by the listener.

    http

    LoadBalancerId

    string

    The ID of the CLB instance.

    lb-bp1b6c719dfa****

    ListenerPort

    integer

    The listener port.

    80

    AclId

    string

    The ID of the access control list (ACL).

    acl-a2do9e413e0spzasx****

    Scheduler

    string

    The scheduling algorithm. Valid values:

    • wrr: Backend servers with higher weights receive more requests than those with lower weights.

    • rr: Requests are distributed to backend servers in sequence.

    • sch: consistent hashing that is based on source IP addresses. Requests from the same source IP address are distributed to the same backend server.

    • tch: specifies consistent hashing based on the source IP address, destination IP address, source port, and destination port. Requests that have the same four factors are distributed to the same backend server.

    • qch: specifies consistent hashing based on Quick UDP Internet Connection (QUIC) IDs. Requests that contain the same QUIC ID are scheduled to the same backend server.

    Note

    Only high-performance CLB instances support the sch, tch, and qch consistent hashing algorithms.

    wrr

    Bandwidth

    integer

    The maximum bandwidth of the listener. Unit: Mbit/s.

    -1

    Description

    string

    The description of the listener.

    test

    AclStatus

    string

    Indicates whether access control is enabled. Valid values:

    • on

    • off

    off

    BackendServerPort

    integer

    The port of the backend server.

    Note

    This parameter takes effect only when the VServerGroupId and MasterSlaveServerGroupId parameters are both empty.

    80

    AclIds

    array

    The IDs of the ACLs.

    HTTPListenerConfig

    object

    The configurations of the HTTP listener.

    HealthCheckHttpVersion

    string

    The HTTP version for health checks.

    HTTP 1.0

    XForwardedFor_ClientSrcPort

    string

    Indicates whether the XForwardedFor_ClientSrcPort header is used to retrieve the client port. Valid values:

    • on

    • off

    on

    Cookie

    string

    The cookie configured on the server.

    B490B5EBF6F3CD402E515D22BCDA****

    Gzip

    string

    Indicates whether GZIP compression is enabled. Valid values:

    • on

    • off

    on

    HealthCheckConnectPort

    integer

    The port that is used for health checks.

    Note

    This parameter takes effect only when HealthCheck is set to on.

    8080

    HealthCheckTimeout

    integer

    The maximum timeout period of a health check. Unit: seconds.

    3

    HealthCheckType

    string

    The protocol that you want to use for health checks.

    tcp

    CookieTimeout

    integer

    The maximum amount of time to wait before the session cookie expires. Unit: seconds.

    Valid values: 1 to 86400.

    500

    HealthCheckDomain

    string

    The domain name that is used for health checks.

    www.example.com

    UnhealthyThreshold

    integer

    The number of times that a healthy backend server must consecutively fail health checks before it is declared unhealthy. In this case, the health check status of the backend server changes from success to fail.

    Valid values: 2 to 10.

    4

    XForwardedFor_SLBID

    string

    Indicates whether the SLB-ID header is used to retrieve the ID of the CLB instance. Valid values:

    • on

    • off

    on

    ForwardPort

    integer

    The listener port that is used for HTTP-to-HTTPS redirection.

    Note

    If the ListenerForward parameter is set to off, this parameter is not returned.

    80

    HealthCheckHttpCode

    string

    The HTTP status code that indicates a healthy backend server.

    http_2xx,http_3xx

    ListenerForward

    string

    Indicates whether HTTP-to-HTTPS redirection is enabled for the listener. Valid values:

    • on

    • off

    on

    XForwardedFor

    string

    Indicates whether the X-Forwarded-For header is used to preserve client IP addresses. Valid values:

    • on

    • off

    on

    IdleTimeout

    integer

    The timeout period of an idle connection. Unit: seconds. Valid values: 1 to 60.

    If no request is received within the specified timeout period, CLB closes the connection. When a request is received, CLB establishes a new connection.

    15

    RequestTimeout

    integer

    The timeout period of a request. Unit: seconds. Valid values: 1 to 180.

    If no response is received from a backend server during the request timeout period, CLB sends the HTTP 504 status code to the client.

    60

    HealthCheckInterval

    integer

    The interval at which health checks are performed. Unit: seconds.

    5

    XForwardedFor_SLBPORT

    string

    Indicates whether the XForwardedFor_SLBPORT header is used to retrieve the listener port of the CLB instance. Valid values:

    • on

    • off

    on

    HealthCheckURI

    string

    The URI that is used for health checks.

    /test/index.html

    StickySessionType

    string

    The method used to handle the cookie. Valid values:

    • insert: inserts a cookie. CLB inserts the SERVERID cookie to the HTTP or HTTPS response to the first request from a client. Subsequent requests that carry the SERVERID cookie from the client are forwarded to the same backend server as the first request.

    • server: rewrites the original cookie. CLB rewrites the custom cookies in requests from a client. Subsequent requests from the client that carry the new cookie are forwarded to the same backend server as the first request.

    insert

    HealthyThreshold

    integer

    The number of times that an unhealthy backend server must consecutively pass health checks before it is declared healthy. In this case, the health check status of the backend server changes from fail to success.

    Valid values: 2 to 10.

    4

    XForwardedFor_proto

    string

    Indicates whether the X-Forwarded-Proto header is used to obtain the listener protocol. Valid values:

    • on

    • off

    on

    XForwardedFor_SLBIP

    string

    Indicates whether the SLB-IP header is used to retrieve the VIP of the client. Valid values:

    • on

    • off

    on

    StickySession

    string

    Indicates whether session persistence is enabled. Valid values:

    • on

    • off

    on

    HealthCheckMethod

    string

    The health check method. Valid values: head and get.

    get

    HealthCheck

    string

    Indicates whether the health check feature is enabled. Valid values:

    • on

    • off

    on

    HTTPSListenerConfig

    object

    The configurations of the HTTPS listener.

    XForwardedFor_ClientCertClientVerify

    string

    Indicates whether the XForwardedFor_ClientCertClientVerify header is used to obtain the verification result of the client certificate. Valid values:

    • on

    • off

    off

    HealthCheckHttpVersion

    string

    The HTTP version for health checks.

    HTTP 1.0

    XForwardedFor_ClientSrcPort

    string

    Indicates whether the XForwardedFor_ClientSrcPort header is used to retrieve the client port. Valid values:

    • on

    • off

    off

    Cookie

    string

    The cookie configured on the server.

    B490B5EBF6F3CD402E515D22BCDA****

    Gzip

    string

    Indicates whether GZIP compression is enabled. Valid values:

    • on

    • off

    on

    EnableHttp2

    string

    Indicates whether HTTP 2.0 is enabled. Valid values:

    • on

    • off

    off

    CACertificateId

    string

    The ID of the CA certificate.

    idkp-234-cn-test-0****

    HealthCheckConnectPort

    integer

    The port that is used for health checks.

    8080

    HealthCheckTimeout

    integer

    The timeout period of a health check response. Unit: seconds.

    3

    HealthCheckType

    string

    The protocol that you want to use for health checks.

    tcp

    CookieTimeout

    integer

    The maximum amount of time to wait before the session cookie expires. Unit: seconds.

    Valid values: 1 to 86400.

    500

    HealthCheckDomain

    string

    The domain name that is used for health checks.

    www.example.com

    UnhealthyThreshold

    integer

    The number of times that a healthy backend server must consecutively fail health checks before it is declared unhealthy. In this case, the health check status of the backend server changes from success to fail.

    Valid values: 2 to 10.

    4

    XForwardedFor_SLBID

    string

    Indicates whether the SLB-ID header is used to retrieve the ID of the CLB instance. Valid values:

    • on

    • off

    on

    XForwardedFor_ClientCertSubjectDN

    string

    Indicates whether the XForwardedFor_ClientCertSubjectDN header is used to obtain information about the owner of the client certificate. Valid values:

    • on

    • off

    off

    HealthCheckHttpCode

    string

    The HTTP status code that indicates a healthy backend server.

    http_2xx,http_3xx

    XForwardedFor_ClientCertFingerprint

    string

    Indicates whether the XForwardedFor_ClientCertFingerprint header is used to obtain the fingerprint of the client certificate. Valid values:

    • on

    • off

    off

    XForwardedFor

    string

    Indicates whether the X-Forwarded-For header is used to retrieve client IP addresses. Valid values:

    • on

    • off

    on

    RequestTimeout

    integer

    The request timeout period. Unit: seconds. Valid values: 1 to 180.

    If no response is received from a backend server during the request timeout period, CLB sends the HTTP 504 status code to the client.

    60

    IdleTimeout

    integer

    The timeout period of an idle connection. Unit: seconds. Valid values: 1 to 60.

    If no request is received within the specified timeout period, CLB closes the connection. When a request is received, CLB establishes a new connection.

    15

    ServerCertificateId

    string

    The ID of the server certificate.

    idkp-123-cn-test-0****

    HealthCheckInterval

    integer

    The interval at which health checks are performed. Unit: seconds.

    5

    XForwardedFor_SLBPORT

    string

    Indicates whether the XForwardedFor_SLBPORT header is used to retrieve the listener port of the CLB instance. Valid values:

    • on

    • off

    off

    HealthCheckURI

    string

    The URI that is used for health checks.

    /test/index.html

    StickySessionType

    string

    The method used to handle the cookie.

    • insert: inserts a cookie. CLB inserts the SERVERID cookie to the HTTP or HTTPS response to the first request from a client. Subsequent requests that carry the SERVERID cookie from the client are forwarded to the same backend server as the first request.

    • server: rewrites the original cookie. CLB rewrites the custom cookies in requests from a client. Subsequent requests from the client that carry the new cookie are forwarded to the same backend server as the first request.

    insert

    XForwardedFor_ClientCertIssuerDN

    string

    Indicates whether the XForwardedFor_ClientCertIssuerDN header is used to obtain information about the authority that issues the client certificate. Valid values:

    • on

    • off

    off

    HealthyThreshold

    integer

    The number of times that an unhealthy backend server must consecutively pass health checks before it is declared healthy. In this case, the health check status of the backend server changes from fail to success.

    Valid values: 2 to 10.

    4

    XForwardedFor_proto

    string

    Indicates whether the X-Forwarded-Proto header is used to obtain the listener protocol. Valid values:

    • on

    • off

    on

    XForwardedFor_SLBIP

    string

    Indicates whether the SLB-IP header is used to retrieve the VIP of the client. Valid values:

    • on

    • off

    on

    StickySession

    string

    Indicates whether session persistence is enabled. Valid values:

    • on:

    • off

    on

    HealthCheckMethod

    string

    The health check method.

    get

    TLSCipherPolicy

    string

    A TLS security policy contains TLS protocols and cipher suites available for HTTPS.

    • tls_cipher_policy_1_0:

      Supported TLS versions: TLSv1.0, TLSv1.1, and TLSv1.2.

      Supported cipher suites: ECDHE-RSA-AES128-GCM-SHA256, ECDHE-RSA-AES256-GCM-SHA384, ECDHE-RSA-AES128-SHA256, ECDHE-RSA-AES256-SHA384, AES128-GCM-SHA256, AES256-GCM-SHA384, AES128-SHA256, AES256-SHA256, ECDHE-RSA-AES128-SHA, ECDHE-RSA-AES256-SHA, AES128-SHA, AES256-SHA, and DES-CBC3-SHA.

    • tls_cipher_policy_1_1:

      Supported TLS versions: TLSv1.1 and TLSv1.2.

      Supported cipher suites: ECDHE-RSA-AES128-GCM-SHA256, ECDHE-RSA-AES256-GCM-SHA384, ECDHE-RSA-AES128-SHA256, ECDHE-RSA-AES256-SHA384, AES128-GCM-SHA256, AES256-GCM-SHA384, AES128-SHA256, AES256-SHA256, ECDHE-RSA-AES128-SHA, ECDHE-RSA-AES256-SHA, AES128-SHA, AES256-SHA, and DES-CBC3-SHA.

    • tls_cipher_policy_1_2

      Supported TLS version: TLSv1.2.

      Supported cipher suites: ECDHE-RSA-AES128-GCM-SHA256, ECDHE-RSA-AES256-GCM-SHA384, ECDHE-RSA-AES128-SHA256, ECDHE-RSA-AES256-SHA384, AES128-GCM-SHA256, AES256-GCM-SHA384, AES128-SHA256, AES256-SHA256, ECDHE-RSA-AES128-SHA, ECDHE-RSA-AES256-SHA, AES128-SHA, AES256-SHA, and DES-CBC3-SHA.

    • tls_cipher_policy_1_2_strict

      Supported TLS version: TLSv1.2.

      Supported cipher suites: ECDHE-RSA-AES128-GCM-SHA256, ECDHE-RSA-AES256-GCM-SHA384, ECDHE-RSA-AES128-SHA256, ECDHE-RSA-AES256-SHA384, ECDHE-RSA-AES128-SHA, and ECDHE-RSA-AES256-SHA.

    • tls_cipher_policy_1_2_strict_with_1_3

      Supported TLS versions: TLSv1.2 and TLSv1.3.

      Supported cipher suites: TLS_AES_128_GCM_SHA256, TLS_AES_256_GCM_SHA384, TLS_CHACHA20_POLY1305_SHA256, TLS_AES_128_CCM_SHA256, TLS_AES_128_CCM_8_SHA256, ECDHE-ECDSA-AES128-GCM-SHA256, ECDHE-ECDSA-AES256-GCM-SHA384, ECDHE-ECDSA-AES128-SHA256, ECDHE-ECDSA-AES256-SHA384, ECDHE-RSA-AES128-GCM-SHA256, ECDHE-RSA-AES256-GCM-SHA384, ECDHE-RSA-AES128-SHA256, ECDHE-RSA-AES256-SHA384, ECDHE-ECDSA-AES128-SHA, ECDHE-ECDSA-AES256-SHA, ECDHE-RSA-AES128-SHA, and ECDHE-RSA-AES256-SHA.

    tls_cipher_policy_1_0

    HealthCheck

    string

    Indicates whether the health check feature is enabled. Valid values:

    • on

    • off

    on

    TCPListenerConfig

    object

    The configurations of the TCP listener.

    HealthCheckHttpCode

    string

    The HTTP status code that indicates a healthy backend server.

    http_2xx,http_3xx

    ConnectionDrainTimeout

    integer

    The timeout period of connection draining. Unit: seconds.

    Value values: 10 to 900.

    300

    PersistenceTimeout

    integer

    Indicates whether session persistence is enabled. Unit: seconds.

    Valid values: 0 to 3600.

    0 indicates that session persistence is disabled.

    0

    HealthCheckInterval

    integer

    The interval between two consecutive health checks. Unit: seconds.

    5

    HealthCheckURI

    string

    The URI that is used for health checks.

    /test/index.html

    HealthCheckConnectPort

    integer

    The port that is used for health checks.

    8080

    EstablishedTimeout

    integer

    The timeout period of a connection. Unit: seconds.

    500

    HealthCheckType

    string

    The protocol that you want to use for health checks.

    tcp

    HealthCheckConnectTimeout

    integer

    The timeout period of health checks. Unit: seconds.

    Valid values: 1 to 300.

    100

    MasterSlaveServerGroupId

    string

    The ID of the primary/secondary server group associated with the listener.

    rsp-0bfucw*****

    HealthyThreshold

    integer

    The number of times that an unhealthy backend server must consecutively pass health checks before it is declared healthy. In this case, the health check status of the backend server changes from fail to success.

    Valid values: 2 to 10.

    4

    HealthCheckDomain

    string

    The domain name that is used for health checks.

    www.example.com

    UnhealthyThreshold

    integer

    The number of times that a healthy backend server must consecutively fail health checks before it is declared unhealthy. In this case, the health check status of the backend server changes from success to fail.

    Valid values: 2 to 10.

    4

    ConnectionDrain

    string

    Indicates whether connection draining is enabled. Valid values:

    • on

    • off

    off

    HealthCheckMethod

    string

    The health check method.

    get

    HealthCheck

    string

    Indicates whether the health check feature is enabled. Valid values:

    • on

    • off

    on

    ProxyProtocolV2Enabled

    string

    Indicates whether the Proxy protocol is used to pass source client IP addresses to backend servers. Valid values:

    • true: enables the burst feature for the data disk.

    • false: The task is not being retried.

    false

    UDPListenerConfig

    object

    The configurations of the UDP listener.

    ConnectionDrainTimeout

    integer

    The configurations of the UDP listener.

    Value values: 10 to 900.

    300

    HealthCheckInterval

    integer

    The interval between two consecutive health checks. Unit: seconds.

    5

    HealthCheckExp

    string

    The response string of UDP health checks.

    ok

    HealthCheckConnectPort

    integer

    The port that is used for health checks.

    8080

    HealthCheckConnectTimeout

    integer

    The timeout period for a health check response.

    100

    MasterSlaveServerGroupId

    string

    The ID of the primary/secondary server group that is associated with the listener.

    rsp-0bfucw****

    HealthyThreshold

    integer

    The number of times that a backend server must consecutively pass health checks before it is declared healthy.

    4

    UnhealthyThreshold

    integer

    The number of times that a backend server must consecutively fail health checks before it is declared unhealthy.

    4

    ConnectionDrain

    string

    Indicates whether connection draining is enabled. Valid values:

    • on

    • off

    off

    HealthCheckReq

    string

    The request string of UDP health checks.

    hello

    HealthCheck

    string

    Indicates whether the health check feature is enabled. Valid values:

    • on

    • off

    on

    ProxyProtocolV2Enabled

    string

    Indicates whether the Proxy protocol is used to pass source client IP addresses to backend servers. Valid values:

    • true: enables the burst feature for the data disk.

    • false: The task is not being retried.

    false

    Tags

    array<object>

    The list of tags.

    object

    The list of tags.

    TagValue

    string

    The tag value.

    TestValue

    TagKey

    string

    The tag key.

    TestKey

    Error codes

    HTTP status code

    Error code

    Error message

    Description

    400

    IllegalParam.ListenerProtocol

    The param of ListenerProtocol is illegal.

    The specified ListenerProtocol is invalid. Check the parameter constraints and try again.

    400

    IllegalParam.MaxResults

    The param of MaxResults is illegal.

    The specified MaxResults is invalid. Check the parameter constraints and try again.

    400

    IllegalParam.NextToken

    The param of NextToken is illegal.

    The specified NextToken is invalid. Check the parameter constraints and try again.

    400

    IllegalParamSize.LoadBalancerId

    The param size of LoadBalancerId is illegal.

    The specified LoadBalancerId is invalid. Check the parameter constraints and try again.

    400

    MissingParam.TagKey

    The param of TagKey is missing.

    403

    UnauthorizedRegion

    The specified region of is not authorized.

    The specified region is not visible.

    See Error Codes for a complete list.

    Release notes

    See Release Notes for a complete list.