Network and ACLs

Attaining a fully secure Couchbase Server network-environment requires the proper configuration of IP tables and ports; the use of IPSec; the establishment of firewalls; the limiting of access to critical files; and the secure maintenance of passwords.

Establishing Firewalls and Protecting Files

The following measures are strongly recommended:

Set up a firewall to block epmd port 4369 from access from outside the cluster-network.
Set up a firewall to block erlang ports from access from outside the cluster-network. These ports are configurable: in the default installation, their range is: 21100 to 21299.
Restrict access to the following directories:
- On Linux: /opt/couchbase
- On Mac OS X: /Users/<user>/Library/Application Support/Couchbase/var/lib/couchbase, and /Applications/Couchbase Server.app/Contents/Resources/couchbase-core
- On Windows (assuming the default installation-location has been used): C:\Program Files\Couchbase Server\
Ensure the confidentiality of passwords defined by the Full Administrator at cluster-initiallization; of all others used for the Admin and Cluster Admin roles; and of the master password. See Secret-Management for details on how to define and use the master password.

Securing the Network

To secure the network on which your Couchbase Server-cluster resides:

Allow administrative access to Couchbase Server only through specific machines, such as jump servers. To perform auditing on access-attempts made from these machines, turn on the OS-level auditing facility on each.
Use IPSec on your local network. For guidance, consult the following online information-resources:

Controlling Access to Files

To restrict user-access to files and directories, traditional file-permissions can be used. Additionally, RedHat Linux provides the following options:

Configuring IP Tables

SSH-access to Couchbase Server and access to the Couchbase Server administrative ports (8091 and 8092) can be restricted to specified machines. Such restrictions can be established either at the network or at the system level, using IP tables rules. Specifically, you can either:

Execute the iptables command.

Edit the file /etc/sysconfig/iptables:

##allow everyone to access port 80 and 443##
      -A INPUT -m state --state NEW -p tcp --dport 80 -j ACCEPT
      -A INPUT -m state --state NEW -p tcp --dport 443 -j ACCEPT

For more information, see IP tables rules. Additionally, a sample of IP tables rules can be found in this blog.

Important Couchbase Server-Ports

The following table lists a subset of Couchbase Server ports, access to which may need to be controlled. For a complete list of Couchbase Server ports, see Network Configuration.

Table 1. Important Couchbase Ports
Port	Description	Node to node	Node to client
8091	Web administration port	Yes	Yes
8092	Couchbase API port	Yes	Yes
8093	Used by query services for REST/HTTP traffic.	Yes	Yes
11207	Internal/external bucket port for SSL	No	Yes
11209	Internal bucket port	Yes	No
11210	Internal/external bucket port	Yes	Yes
11211	Client interface (proxy)	No	Yes
11214	Incoming SSL proxy	No	No
11215	Internal outgoing SSL proxy	No	No
18091	Internal REST HTTPS for SSL	No	Yes
18092	Internal CAPI HTTPS for SSL	No	Yes
4369	Erlang port mapper (epmd)	Yes	No
21100 to 21199 (inclusive)	Node data exchange	Yes	No

A sample script for configuring the IP-tables firewall-settings is located in the following blog posting: IPTables Firewall Settings for Couchbase DB and Couchbase Mobile Sync_gateway

Securing On-Disk Data

Critical data-locations should be protected by means of transparent data encryption technologies; provided by 3rd party on-disk encryption software-vendors, such as Vormetric. For details, see Encryption at Rest. Also see the webinar provided at Understanding Database Encryption with Couchbase and Vormetric.