Configuring proxy to Mattermost transport encryption#

Also available in legacy Mattermost Enterprise Edition E20

Mattermost is able to encrypt the traffic between the proxy and the application server using TLS.

Prerequisites#

Operational Mattermost server or cluster.
Authentication credentials for Mattermost user on application server.

Example environment#

In this scenario there is one Mattermost application server and one NGINX server, both running Ubuntu 20.04, with the following IPs:

transport-encryption-mattermost1: 10.10.250.146
transport-encryption-nginx: 10.10.250.107

Configuring NGINX#

On the NGINX server, connect to both servers with a sudo or root user. Open the Mattermost proxy configuration and search for the following line twice:

proxy_pass http://backend;

Change the protocol from http to https:

proxy_pass https://backend;

Afterwards do not reload the NGINX server yet to minimize the downtime of the service.

Configuring Mattermost#

On the Mattermost server, change to the config directory of Mattermost and generate a self-signed certificate that will be used to encrypt the traffic between the proxy server and the application server.

Note: Alternatively you can sign a certificate from your company’s CA.

$ cd /opt/mattermost/config
$ openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -nodes
$ chown root:mattermost *.pem
$ chmod 640 *.pem

Once complete, open the file config.json and modify the values ConnectionSecurity, TLSCertFile and TLSKeyFile in the ServiceSettings section.

Before

{
    "ServiceSettings": {
        "SiteURL": "https://transport-encryption.dev.example.com",
        "WebsocketURL": "",
        "LicenseFileLocation": "",
        "ListenAddress": ":8065",
        "ConnectionSecurity": "",
        "TLSCertFile": "",
        "TLSKeyFile": "",
        "...":"..."
    },
    "...":"..."
}

After

{
    "ServiceSettings": {
        "SiteURL": "https://transport-encryption.dev.example.com",
        "WebsocketURL": "",
        "LicenseFileLocation": "",
        "ListenAddress": ":8065",
        "ConnectionSecurity": "TLS",
        "TLSCertFile": "/opt/mattermost/config/cert.pem",
        "TLSKeyFile": "/opt/mattermost/config/key.pem",
        "...":"..."
    },
    "...":"..."
}

Restart the Mattermost server and ensure it’s up and running:

$ sudo systemctl restart mattermost
$ systemctl status mattermost
● mattermost.service - Mattermost
   Loaded: loaded (/lib/systemd/system/mattermost.service; static; vendor preset: enabled)
   Active: active (running) since Mon 2019-10-28 16:45:29 UTC; 1h 15min ago
   [...]

Finally, on the NGINX server, reload the configuration to ensure that requests are sent on HTTPS:

$ sudo systemctl reload nginx