F5 gtm what is a listener




















In certain circumstances, you might want to ensure that a user remains with a given set of resources throughout the session. For example, a user attempting to conduct on online banking transaction needs to remain with the same set of resources to ensure that the transaction is completed successfully. When you design your network, ensure that this particular pool is kept in reserve and not used as part of the normal global server load balancing.

All of the resources on your network are associated with a data center. GTM uses that data to conduct load balancing and route client requests to the best-performing resource based on different factors. GTM might send all requests to one data center when another data center is down.

Alternatively, GTM might send a request to the data center that has the fastest response time. A third option might be for GTM to send a request to the data center that is located closest to the client's source address. A server defines a physical system on the network. Servers contain the virtual servers that are the ultimate destinations of DNS name resolution requests. A host is a network resource that is not a part of the BIG-IP product family and does not provide load balancing.

A virtual server is a specific IP address and port number that points to a resource on the network. In the case of host servers, this IP address and port number likely point to the resource itself. With load balancing systems, virtual servers are often proxies that allow the load balancing server to manage a resource request across a multitude of resources.

A pool is a collection of virtual servers that can reside on multiple servers. A virtual server is a combination of IP address and port number that points to a specific resource on the network. When you add a virtual server to a pool, it becomes a pool member.

A pool member is a virtual server that has attributes that pertain to the virtual server only in the context of the pool. A virtual server can be a member of multiple pools and have different attributes in each pool. A link is a logical representation of a physical device router that connects your network to the Internet.

A distributed application is a collection of one or more wide IPs, data centers, and links that serve as a single application to a web site visitor. Configuring a distributed application provides several advantages:. If the New York data center goes offline, a wide IP in that data center becomes unavailable.

A distributed application associated with that wide IP also becomes unavailable. Consequently, the system does not send resolution requests to any of the distributed application resources, until the entire application becomes available again. With the ZoneRunner utility, you can:. The ZoneRunner utility updates named. A DNS view is a modification of a nameserver configuration based on the community attempting to access it. Using views, you can build multiple nameserver configurations on the same server, and have those configurations apply dynamically when the request originates from a specified source.

If your DNS handles requests from both inside and outside your company, you can create two views: internal and external. The first generation of a key has an ID of 0 zero. Over time, each generation of a key overlaps the previous generation of the key ensuring that GTM can respond to a DNSSEC query even if one generation of a key becomes unavailable. The value of the TTL time-to-live of a key specifies how long a client resolver can cache the key. My Support. About listeners A listener is a specialized virtual server that passively checks for DNS packets on port 53 and the IP address you assign to the listener.

Listener configuration example. About wildcard listeners A wildcard listener is a special listener that is assigned an IP address of 0. Prober pool statistics displayed per system. About Prober pool status The status of a Prober pool also indicates the status of the members of the pool. Flow of probe process. Converting a statistics collection server to a Prober pool automatically In version Protocols and ports used by big3d during communications with local DNS servers This table describes the protocols and ports the big3d agent uses to communicate with an LDNS when collecting path data for the local DNS servers.

Table 1. Use to replace a single character, except a dot. Valid uses of wildcard characters for the wide IP name www. Using wildcard characters in wide IPs to minimize maintenance tasks Determine the domain names and aliases for which you want to configure wide IPs. Create a wide IP using wildcard characters in the name to represent a domain when you have a large quantity of aliases that you want to use for the domain.

This reduces the number of aliases you have to add to the configuration. About persistence connections Most load balancing methods divide DNS name resolution requests among available pools or virtual servers.

Configuring a wide IP with a last resort pool Ensure that a pool of virtual servers that is not part of the normal global server load balancing operations exists in the configuration. Create a wide IP to map a FQDN to one or more pools of virtual servers that host the content of the domain, and assign a last resort pool to the wide IP.

About data centers All of the resources on your network are associated with a data center. Tip: The resources associated with a data center are available only when the data center is also available. About servers A server defines a physical system on the network. Third-party load balancing systems A third-party load balancing system is any system, other than a BIG-IP system, that supports and manages virtual servers on the network. About third-party host servers A host is a network resource that is not a part of the BIG-IP product family and does not provide load balancing.

Windows NT 4. About virtual servers A virtual server is a specific IP address and port number that points to a resource on the network. Configuring virtual server availability to be dependent on the status of other virtual servers Ensure that multiple virtual servers are configured on the server. Determine the virtual servers upon which you want the availability of a virtual server to be dependent.

Topics plus plus. Application Delivery. What's Devcentral. Search Loading. View This Post. November 18, at PM. Any help is appreciated. Thank you, Mickey. Top Rated Answers. There are two VLANs, named external and guests. All Answers. While you can do that you don't have to. I don't believe that is a requirement.

Your NS records will be whatever you setup as your listener whether that is a self ip or some other IP. For clarification I would point out that the statement "A listener object that is not defined as a self IP address cannot direct name resolution requests to BIND. The system receives traffic sent to this IP address and processes it as needed. This option is required. The options are yes or no. The default value is no. The default value is none. Note: If the strict- updates option is enabled on the application service that owns the object, you cannot modify or delete the listener.

Only the application service can modify or delete the listener. If not specified, the default value is all for both sides. The default value is enabled. Note: When you disable a listener, the listener no longer accepts new connection requests.

However, it allows current connections to finish processing before going to a down state. See help glob for a description of glob expression syntax. The options are udp or tcp. The default value is udp. This setting is required for a network listener. The netmask clarifies whether the host bit is an actual zero or a wildcard representation.

The default value is



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