How To Securely Manage Secrets with HashiCorp Vault on Ubuntu 16.04


Memory item caching systems like Memcached can optimize backend database performance by temporarily information that is storing memory, retaining frequently or recently requested records. In this real means, they decrease the amount of direct needs towards databases.

Because systems like Memcached can donate to denial of solution assaults if improperly configured, it is vital to secure your servers that are memcached. In this guide, we will cover how to protect your Memcached server by binding your installation to a local or network that is private and producing a certified individual for the Memcached example.


This guide assumes you have actually a host setup with a non-root sudo individual and a firewall that is basic. If that is not the case, set up and install the ( that is following******)

With these prerequisites in position, you will end up willing to install and secure your Memcached host.

Installing Memcached from Certified Repositories

If that you don’t have Memcached set up on your own host, you’ll do the installation through the formal CentOS repositories. First, make sure your package that is local index updated:

Next, install the package that is official follows:

  • sudo yum install memcached

We also can install libmemcached, a collection providing you with a few tools to utilize your server that is memcached:(******)

  • sudo yum install libmemcached

Memcached should now be set up as something on your own host, and tools that'll permit you to test its connectivity. We could now proceed to securing its setup settings.

Securing Memcached Configuration Settings

To make certain that our Memcached example is paying attention regarding interface that is local*********), we will modify the OPTIONS variable in the configuration file located at /etc/sysconfig/memcached. We shall additionally disable the UDP listener. Both these actions will protect our host from denial of solution assaults.

You can start /etc/sysconfig/memcached with vi:

  • sudo vi /etc/sysconfig/memcached

Locate the OPTIONS adjustable, that'll at first seem like this:


. . .

Binding to your regional system program will limit traffic to consumers regarding machine that is same. We shall repeat this with the addition of -l to your OPTIONS adjustable. This can be too restrictive for many surroundings, nonetheless it could make a starting that is good as a security measure.

Because UDP protocol is more effective for denial of solution assaults than TCP, we could additionally disable the UDP listener. To get this done, we are going to include the -U 0 parameter to your OPTIONS adjustable. The file completely should seem like this:


OPTIONS="-l -U 0" 

Save and shut the file while done.

Restart your service that is memcached to your modifications:

  • sudo systemctl restart memcached

Verify that Memcached happens to be bound to your interface that is local paying attention limited to TCP connections by typing:

You should start to see the output that is following******)


Active online connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program title . . . tcp 0 0* LISTEN 2383/memcached . . .

This verifies that memcached is likely to the target only using TCP.

Adding Authorized Customers

To include authenticated users towards service that is memcached is possible to use Simple Authentication and Security Layer (SASL), a framework that de-couples authentication procedures from application protocols. We will enable SASL within our configuration that is memcached file then proceed to including a person with verification qualifications.

Configuring SASL Help

We can first test the connectivity of our instance that is memcached with memstat demand. This can assist united states establish that SASL and individual verification are enabled directly after we make modifications to your setup files.

To be sure Memcached is ready to go, kind the ( that is following******)

  • memstat --servers=""

You should see production just like the ( that is following******)


Server: (11211) pid: 3831 uptime: 9 time: 1520028517 variation: 1.4.25 . . .

Now we could proceed to allowing SASL. First, we could include the -S parameter to your OPTIONS adjustable in /etc/sysconfig/memcached, that'll allow SASL. Start the file once again:

  • sudo vi /etc/sysconfig/memcached

We will include both -S and -vv parameters to your OPTIONS adjustable. The -vv choice provides output that is verbose /var/log/memcached, which will surely help united states even as we debug. Include these choices to the OPTIONS adjustable the following:


. . .
OPTIONS="-l -U 0 -S -vv" 

Save and shut the file.

Restart the Memcached solution:

  • sudo systemctl restart memcached

Next, we could take a good look at the logs to make sure that SASL help was enabled:

  • sudo journalctl -u memcached

You should start to see the line that is following showing that SASL help was initialized:


. . . Mar 05 18:16:11 memcached-server memcached[3846]: Initialized SASL. . . .

We can check out the connectivity once again, but because SASL was initialized, this demand should fail without verification:

  • memstat --servers=""

This demand shouldn't create production. We could form the next to check on its status:

$? will usually get back the exit rule associated with command that is last exited. Typically, anything besides 0 indicates process failure. In this full situation, we must see an exit status of 1, which informs united states your memstat demand failed.

Adding an Authenticated Consumer

Now we could install two packages that'll let us utilize the Cyrus SASL Library and its own verification mechanisms, including plugins that help PLAIN verification schemes. These packages, cyrus-sasl-devel and cyrus-sasl-plain, enables united states generate and authenticate our individual. Install the packages by typing:

  • sudo yum install cyrus-sasl-devel cyrus-sasl-plain

Next, we are going to produce the directory and file that Memcached will search for its SASL setup settings:

  • sudo mkdir/etc/sasl2 that is-p
  • sudo vi /etc/sasl2/memcached.conf

Add the next to your SASL setup file:


mech_list: simple
log_level: 5
sasldb_path: /etc/sasl2/memcached-sasldb2

In addition to indicating our logging degree, we are going to set mech_list to plain, which informs Memcached so it should make use of its password that is own file verify a plaintext password. We shall additionally specify the trail to your individual database file we will generate next. Save and shut the file while completed.

Now we are going to produce a SASL database with your individual qualifications. We are going to make use of the saslpasswd2 demand in order to make a entry that is new our user in our database using the -c option. Our user will be sammy here, but you can replace this true title with your own personal individual. Utilising the -f choice, we are going to specify the trail to your database, which is the trail we occur /etc/sasl2/memcached.conf:

  • sudo saslpasswd2 -a memcached -c -f /etc/sasl2/memcached-sasldb2 sammy

Finally, you want to supply the memcached individual ownership on the SASL database:

  • sudo chown memcached:memcached /etc/sasl2/memcached-sasldb2

Restart the Memcached solution:

  • sudo systemctl restart memcached

Running memstat once again will verify whether our verification procedure worked. This time around we shall run it with your verification qualifications:

  • memstat --servers="" --username=sammy --password=your_password

You should see production just like the ( that is following******)


Server: (11211) pid: 3831 uptime: 9 time: 1520028517 variation: 1.4.25 . . .

Our Memcached solution has become effectively operating with SASL help and individual verification.

Allowing Access Throughout The Personal System

We have actually covered just how to configure Memcached to concentrate regarding interface that is local which can prevent denial of service attacks by protecting the Memcached interface from exposure to outside parties. There may be instances where you shall need certainly to enable access off their servers, nonetheless. In cases like this, you'll adjust your setup settings to bind Memcached to your network interface that is private.

Limiting internet protocol address Access With Firewalls

Before you adjust your setup settings, it really is a idea that is good set up firewall rules to limit the machines that can connect to your Memcached server. Then you do not need to adjust your firewall rules if you followed the prerequisites and installed FirewallD on your server and do not plan on connecting to Memcached from another host. Your standalone Memcached example must be paying attention on, because of the OPTIONS variable we defined early in the day, and there should for that reason be no issues about incoming traffic. Then you will need to make changes to your firewall settings using the firewall-cmd command if you plan to allow access to your Memcached server from other hosts, however.

Begin with the addition of a passionate Memcached area towards firewalld policy:

  • sudo firewall-cmd --permanent --new-zone=memcached

Then, specify which slot you'd like to keep available. Memcached utilizes slot 11211 automagically:

  • sudo firewall-cmd --permanent --zone=memcached --add-port=11211/tcp

Next, specify the IP that is private that should be allowed to access Memcached. For this, you shall have to know your client host's personal internet protocol address:

  • sudo firewall-cmd --permanent --zone=memcached --add-source=client_server_private_IP

Reload the firewall to ensure the rules that are new impact:

  • sudo firewall-cmd --reload

Packets from your own customer's internet protocol address should now be prepared based on the guidelines inside Memcached that is dedicated area. All the connections will likely be prepared by the standard public area.

With these alterations in spot, we could proceed to making the configuration that is necessary to your Memcached solution, binding it to your host's personal networking program.

Binding Memcached to your Private system Interface

The first faltering step in binding to your host's personal networking program will likely be changing the OPTIONS adjustable we set early in the day.

We can start /etc/sysconfig/memcached once again by typing:

  • sudo vi /etc/sysconfig/memcached

Inside, find the OPTIONS adjustable. We could now alter -l to mirror our Memcached host's personal internet protocol address:


. . .
OPTIONS="-l memcached_servers_private_IP -U 0 -S -vv"

Save and shut the file while completed.

Restart the Memcached solution once again:

  • sudo systemctl restart memcached

Check your settings that are new netstat to verify the alteration:


Active online connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program title . . . tcp 0 0 memcached_servers_private_IP:11211* LISTEN 2383/memcached . . .

Test connectivity from your own client that is external to that you can still reach the service. It is a idea that is good additionally always check access from a non-authorized customer to ensure your firewall guidelines work.


In this guide we've covered just how to secure your Memcached host by configuring it to bind towards regional or network that is private, and also by allowing SASL verification.

To find out about Memcached, take a look at task paperwork. To find out more on how to utilize Memcached, see our guide on how best to Install and make use of Memcache on Ubuntu 14.04.

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