Firewalls and Ports

This topic explains how to ensure that your port settings are configured correctly for firewalls when using VMware GEmFire.

There are several different port settings that need to be considered when using firewalls:

Port that the cache server listens on. This is configurable using the cache-server element in cache.xml, on the CacheServer class in Java APIs, and as a command line option to the gfsh start server command.

By default, if not otherwise specified, Tanzu GemFire clients and servers discover each other on a pre-defined port (40404) on the localhost.
Locator port. Tanzu GemFire clients can use the locator to automatically discover cache servers. The locator port is configurable as a command-line option to the gfsh start locator command. Locators are used in the peer-to-peer cache deployments to discover other processes. They can be used by clients to locate servers as an alternative to configuring clients with a collection of server addresses and ports.

By default, if not otherwise specified, Tanzu GemFire locators use the default port 10334.
Since locators start up the cluster, locators must also have their ephemeral port range and TCP port accessible to other members through the firewall.
For clients, you configure the client to connect to servers using the client’s pool configuration. The client’s pool configuration has two options: you can create a pool with either a list of server elements or a list of locator elements. For each element, you specify the host and port. The ports specified must be made accessible through your firewall.

Limiting Ephemeral Ports for Peer-to-Peer Membership

By default, Tanzu GemFire assigns ephemeral ports, that is, temporary ports assigned from a designated range, which can encompass a large number of possible ports. When a firewall is present, the ephemeral port range usually must be limited to a much smaller number, for example six. If you are configuring P2P communications through a firewall, you must also set the TCP port for each process and ensure that UDP traffic is allowed through the firewall.

Properties for Firewall and Port Configuration

This table contains properties potentially involved in firewall behavior, with a brief description of each property.

Configuration area	Property or Setting	Definition
peer-to-peer config	`conserve-sockets`	Specifies whether sockets are shared by the system member's threads.
peer-to-peer config	`locators`	The list of locators used by system members. The list must be configured consistently for every member of the cluster.
peer-to-peer config	`mcast-address`	Address used to discover other members of the cluster. Only used if mcast-port is non-zero. This attribute must be consistent across the cluster.
peer-to-peer config	`mcast-port`	Port used, along with the mcast-address, for multicast communication with other members of the cluster. If zero, multicast is deactivated for data distribution.
peer-to-peer config	`membership-port-range`	The range of ephemeral ports available for unicast UDP messaging and for TCP failure detection in the peer-to-peer cluster.
peer-to-peer config	`tcp-port`	The TCP port to listen on for cache communications.

Configuration Area	Property or Setting	Definition
cache server config	`hostname-for-clients`	Hostname or IP address to pass to the client as the location where the server is listening.
cache server config	`max-connections`	Maximum number of client connections for the server. When the maximum is reached, the server refuses additional client connections.
cache server config	`port` (cache.xml) or `--port` parameter to the `gfsh start server` command	Port that the server listens on for client communication.

Default Port Configurations

Port Name	Related Configuration Setting	Default Port
Cache Server	`port` (cache.xml)	40404
HTTP	`http-service-port`	7070
Locator	`start-locator` (for embedded locators) or `--port` parameter to the `gfsh start locator` command.	if not specified upon startup or in the start-locator property, uses default port 10334
Membership Port Range	`membership-port-range`	41000 to 61000
Memcached Port	`memcached-port`	not set
Multicast	`mcast-port`	0
RMI	`jmx-manager-port`	1099
TCP	`tcp-port`	ephemeral port

Properties for Firewall and Port Configuration in Multi-Site (WAN) Configurations

Each gateway receiver uses a single port to accept connections from gateway senders in other systems. The configuration of a gateway receiver specifies a range of possible port values to use. Tanzu GemFire selects an available port from the specified range when the gateway receiver starts. Configure your firewall so that the full range of possible port values is accessible by gateway senders from across the WAN.

Configuration Area	Property or Setting	Definition
multi-site (WAN) config for gateway sender	hostname-for-senders	Hostname or IP address of the gateway receiver used by gateway senders to connect.
multi-site (WAN) config for locator	remote-locators	List of locators (and their ports) that are available on the remote WAN site.
multi-site (WAN) config for gateway receiver	start-port and end-port (cache.xml) or `–start-port` and `–end-port` parameters to the `gfsh start gateway receiver` command	Port range that the gateway receiver can use to listen for gateway sender communication.