Configure Windows `netsh` Firewall for MongoDB¶

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On Windows Server systems, the netsh program provides methods for managing the Windows Firewall. These firewall rules make it possible for administrators to control what hosts can connect to the system, and limit risk exposure by limiting the hosts that can connect to a system.

This document outlines basic Windows Firewall configurations. Use these approaches as a starting point for your larger networking organization. For a detailed over view of security practices and risk management for MongoDB, see Security.

Overview¶

Windows Firewall processes rules in an ordered determined by rule type, and parsed in the following order:

Windows Service Hardening
Connection security rules
Authenticated Bypass Rules
Block Rules
Allow Rules
Default Rules

By default, the policy in Windows Firewall allows all outbound connections and blocks all incoming connections.

Given the default ports of all MongoDB processes, you must configure networking rules that permit only required communication between your application and the appropriate mongod.exe and mongos.exe instances.

The configuration changes outlined in this document will create rules which explicitly allow traffic from specific addresses and on specific ports, using a default policy that drops all traffic that is not explicitly allowed.

You can configure the Windows Firewall with using the netsh command line tool or through a windows application. On Windows Server 2008 this application is Windows Firewall With Advanced Security in Administrative Tools. On previous versions of Windows Server, access the Windows Firewall application in the System and Security control panel.

The procedures in this document use the netsh command line tool.

Patterns¶

This section contains a number of patterns and examples for configuring Windows Firewall for use with MongoDB deployments. If you have configured different ports using the port configuration setting, you will need to modify the rules accordingly.

Traffic to and from `mongod.exe` Instances¶

This pattern is applicable to all mongod.exe instances running as standalone instances or as part of a replica set. The goal of this pattern is to explicitly allow traffic to the mongod.exe instance from the application server.

netsh advfirewall firewall add rule name="Open mongod port 27017" dir=in action=allow protocol=TCP localport=27017

This rule allows all incoming traffic to port 27017, which allows the application server to connect to the mongod.exe instance.

Windows Firewall also allows enabling network access for an entire application rather than to a specific port, as in the following example:

netsh advfirewall firewall add rule name="Allowing mongod" dir=in action=allow program=" C:\Program Files\MongoDB\Server\3.4\bin\mongod.exe"

You can allow all access for a mongos.exe server, with the following invocation:

netsh advfirewall firewall add rule name="Allowing mongos" dir=in action=allow program=" C:\Program Files\MongoDB\Server\3.4\bin\mongos.exe"

Traffic to and from `mongos.exe` Instances¶

mongos.exe instances provide query routing for sharded clusters. Clients connect to mongos.exe instances, which behave from the client’s perspective as mongod.exe instances. In turn, the mongos.exe connects to all mongod.exe instances that are components of the sharded cluster.

Use the same Windows Firewall command to allow traffic to and from these instances as you would from the mongod.exe instances that are members of the replica set.

netsh advfirewall firewall add rule name="Open mongod shard port 27018" dir=in action=allow protocol=TCP localport=27018

Traffic to and from a MongoDB Config Server¶

Configuration servers, host the config database that stores metadata for sharded clusters. Each production cluster has three configuration servers, initiated using the mongod --configsvr option. [1] Configuration servers listen for connections on port 27019. As a result, add the following Windows Firewall rules to the config server to allow incoming and outgoing connection on port 27019, for connection to the other config servers.

netsh advfirewall firewall add rule name="Open mongod config svr port 27019" dir=in action=allow protocol=TCP localport=27019

Additionally, config servers need to allow incoming connections from all of the mongos.exe instances in the cluster and all mongod.exe instances in the cluster. Add rules that resemble the following:

netsh advfirewall firewall add rule name="Open mongod config svr inbound" dir=in action=allow protocol=TCP remoteip=<ip-address> localport=27019

Replace <ip-address> with the addresses of the mongos.exe instances and the shard mongod.exe instances.

[1]	You also can run a config server by using the `configsrv` value for the `clusterRole` setting in a configuration file.

Traffic to and from a MongoDB Shard Server¶

For shard servers, running as mongod --shardsvr [2] Because the default port number is 27018 when running with the shardsvr value for the clusterRole setting, you must configure the following Windows Firewall rules to allow traffic to and from each shard:

netsh advfirewall firewall add rule name="Open mongod shardsvr inbound" dir=in action=allow protocol=TCP remoteip=<ip-address> localport=27018
netsh advfirewall firewall add rule name="Open mongod shardsvr outbound" dir=out action=allow protocol=TCP remoteip=<ip-address> localport=27018

Replace the <ip-address> specification with the IP address of all mongod.exe instances. This allows you to permit incoming and outgoing traffic between all shards including constituent replica set members to:

all mongod.exe instances in the shard’s replica sets.
all mongod.exe instances in other shards. [3]

Furthermore, shards need to be able make outgoing connections to:

all mongos.exe instances.
all mongod.exe instances in the config servers.

Create a rule that resembles the following, and replace the <ip-address> with the address of the config servers and the mongos.exe instances:

netsh advfirewall firewall add rule name="Open mongod config svr outbound" dir=out action=allow protocol=TCP remoteip=<ip-address> localport=27018

[2]	You can also specify the shard server option with the `shardsvr` value for the `clusterRole` setting in the configuration file. Shard members are also often conventional replica sets using the default port.

[3]	All shards in a cluster need to be able to communicate with all other shards to facilitate chunk and balancing operations.

Provide Access For Monitoring Systems¶

The mongostat diagnostic tool, when running with the --discover needs to be able to reach all components of a cluster, including the config servers, the shard servers, and the mongos.exe instances.
If your monitoring system needs access the HTTP interface, insert the following rule to the chain:
```
netsh advfirewall firewall add rule name="Open mongod HTTP monitoring inbound" dir=in action=allow protocol=TCP remoteip=<ip-address> localport=28017
```
Replace <ip-address> with the address of the instance that needs access to the HTTP or REST interface. For all deployments, you should restrict access to this port to only the monitoring instance.
Optional

For config server mongod instances running with the shardsvr value for the clusterRole setting, the rule would resemble the following:
```
netsh advfirewall firewall add rule name="Open mongos HTTP monitoring inbound" dir=in action=allow protocol=TCP remoteip=<ip-address> localport=28018
```
For config server mongod instances running with the configsvr value for the clusterRole setting, the rule would resemble the following:
```
netsh advfirewall firewall add rule name="Open mongod configsvr HTTP monitoring inbound" dir=in action=allow protocol=TCP remoteip=<ip-address> localport=28019
```

Manage and Maintain Windows Firewall Configurations¶

This section contains a number of basic operations for managing and using netsh. While you can use the GUI front ends to manage the Windows Firewall, all core functionality is accessible is accessible from netsh.

Delete all Windows Firewall Rules¶

To delete the firewall rule allowing mongod.exe traffic:

netsh advfirewall firewall delete rule name="Open mongod port 27017" protocol=tcp localport=27017

netsh advfirewall firewall delete rule name="Open mongod shard port 27018" protocol=tcp localport=27018

List All Windows Firewall Rules¶

To return a list of all Windows Firewall rules:

netsh advfirewall firewall show rule name=all

Reset Windows Firewall¶

To reset the Windows Firewall rules:

netsh advfirewall reset

Backup and Restore Windows Firewall Rules¶

To simplify administration of larger collection of systems, you can export or import firewall systems from different servers) rules very easily on Windows:

Export all firewall rules with the following command:

netsh advfirewall export "C:\temp\MongoDBfw.wfw"

Replace "C:\temp\MongoDBfw.wfw" with a path of your choosing. You can use a command in the following form to import a file created using this operation:

netsh advfirewall import "C:\temp\MongoDBfw.wfw"

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Configure Windows netsh Firewall for MongoDB¶