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How one can arrange a simple and safe reverse proxy with Docker, Nginx & Letsencrypt

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Good rating on SSL Labs


Ever tried establishing some type of server at dwelling? The place you must open a brand new port for each service? And have to recollect what port goes to which service, and what your own home ip is? That is undoubtedly one thing that works, and other people have been doing it for the longest time.

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Nevertheless, wouldn’t or not it’s good to sort plex.instance.com, and have on the spot entry to your media server? That is precisely what a reverse proxy will do for you, and mixing it with Docker, it’s simpler than ever.


Docker & Docker-Compose

It’s best to have Docker model 17.12.0+, and Compose model 1.21.0+.


It’s best to have a website arrange, and have an SSL Certificates related to it. In the event you don’t have one, then observe my information right here on tips on how to get a free one with LetsEncrypt.

What This Article Will Cowl

I’m a agency believer in understanding what you might be doing. There was a time the place I might observe guides, and don’t have any clue on tips on how to troubleshoot failures. If that’s the way you need to do it, right here’s an important tutorial, which covers tips on how to set it up. Whereas my articles are prolonged, you need to find yourself with an understanding of the way it all works.

What you’ll be taught right here, is what a reverse proxy is, tips on how to set it up, and how one can safe it. I do my finest to divide the topic into sections, divided by headers, so be happy to leap over a piece, in case you really feel prefer it. I like to recommend studying the whole article one time first, earlier than beginning to set it up.

What’s a Reverse Proxy?

Common Proxy

Let’s begin with the idea of a daily proxy. Whereas this can be a time period that’s very prevalent within the tech neighborhood, it isn’t the one place it’s used. A proxy implies that data goes via a 3rd celebration, earlier than attending to the situation.

Say that you simply don’t desire a service to know your IP, you should use a proxy. A proxy is a server that has been arrange particularly for this objective. If the proxy server you might be utilizing is positioned in, for instance, Amsterdam, the IP that can be proven to the surface world is the IP from the server in Amsterdam. The one ones who will know your IP are those in command of the proxy server.

Reverse Proxy

To interrupt it into easy phrases, a proxy will add a layer of masking. It’s the identical idea in a reverse proxy, besides as an alternative of masking outgoing connections (you accessing a webserver), it’s the incoming connections (individuals accessing your webserver) that can be masked. You merely present a URL like instance.com, and at any time when individuals entry that URL, your reverse proxy will care for the place that request goes.

Let’s say you may have two servers arrange in your inner community. Server1 is on, and Server2 is on Proper now your reverse proxy is sending requests coming from instance.com to Server1. Sooner or later you may have some updates to the webpage. As an alternative of taking the web site down for upkeep, you simply make the brand new setup on Server2. One you’re completed, you merely change a single line in your reverse proxy, and now requests are despatched to Server2. Assuming the reverse proxy is setup accurately, you need to have completely no downtime.

However maybe the largest benefit of getting a reverse proxy, is that you could have providers operating on a large number of ports, however you solely must open ports 80 and 443, HTTP and HTTPS respectively. All requests can be coming into your community on these two ports, and the reverse proxy will care for the remaining. All of it will make sense as soon as we begin setting the proxy up.

Setting Up the Container

What to Do

To start with, you need to add a brand new service to your docker-compose file. You possibly can name it no matter you like, on this case I’ve chosen reverse. Right here I’ve simply chosen nginx because the picture, nonetheless in a manufacturing atmosphere, it’s often a good suggestion to specify a model in case there are ever any breaking adjustments in future updates.

Then you need to quantity bind two folders. /and so on/nginx is the place all of your configuration recordsdata are saved, and /and so on/ssl/non-public is the place your SSL certificates are saved. It’s VERY vital that your config folder does NOT exist in your host first time you’re beginning the container. Once you begin your container via docker-compose, it should routinely create the folder and populate it with the contents of the container. If in case you have created an empty config folder in your host, it should mount that, and the folder contained in the container can be empty.

Why it Works

There isn’t a lot to this half. Principally it’s like beginning some other container with docker-compose. What you need to discover right here is that you’re binding port 80 and 443. That is the place all requests will are available, and they are going to be forwarded to no matter service you’ll specify.

Configuring Nginx

What to Do

Now you need to have a config folder in your host. Altering to that listing, you need to see a bunch of various recordsdata and a folder known as conf.d. It’s inside conf.d that every one your configuration recordsdata can be positioned. Proper now there’s a single default.conf file, you possibly can go forward and delete that.

Nonetheless inside conf.d, create two folders: sites-available and sites-enabled. Navigate into sites-available and create your first configuration file. Right here we’re going to setup an entry for Plex, however be happy to make use of one other service that you’ve got arrange in case you like. It doesn’t actually matter what the file is known as, nonetheless I favor to call it like plex.conf.

Now open the file, and enter the next:

Go into the sites-enabled listing, and enter the next command:

ln -s ../sites-available/plex.conf .

This can create a symbolic hyperlink to the file within the different folder. Now there’s just one factor left, and that’s to vary the nginx.conf file within the config folder. In the event you open the file, you need to see the next because the final line:

embrace /and so on/nginx/conf.d/*.conf;

Change that to:

embrace /and so on/nginx/conf.d/sites-enabled/*.conf;

As a way to get the reverse proxy to really work, we have to reload the nginx service contained in the container. From the host, run docker exec <container-name> nginx -t. This can run a syntax checker in opposition to your configuration recordsdata. This could output that the syntax is okay. Now run docker exec <container-name> nginx -s reload. This can ship a sign to the nginx course of that it ought to reload, and congratulations! You now have a operating reverse proxy, and will be capable of entry your server at plex.instance.com (assuming that you’ve got forwarded port 80 to your host in your router).

Despite the fact that your reverse proxy is working, you might be operating on HTTP, which gives no encryption in any way. The following half can be tips on how to safe your proxy, and get an ideal rating on SSL Labs.

Why it Works

The Configuration File

As you possibly can see, the plex.conf file consists of two elements. An upstream half and a server half. Let’s begin with the server half. That is the place you might be defining the port receiving the incoming requests, what area this configuration ought to match, and the place it needs to be despatched to.

The best way this server is being arrange, you need to make a file for every service that you simply need to proxy requests to, so clearly you want some strategy to distinguish which file to obtain every request. That is what the server-name directive does. Beneath that we have now the location directive.

In our case we solely want one location, nonetheless you possibly can have as many location directives as you need. Think about you may have a web site with a frontend and a backend. Relying on the infrastructure you’re utilizing, you’ll have the frontend as one container and the backend as one other container. You possibly can then have location / {} which is able to ship requests to the frontend, and location /api/ {} which is able to ship requests to the backend. Instantly you may have a number of providers operating on a single memorable area.

As for the upstream half, that can be utilized for load-balancing. In the event you’re involved in studying extra about how that works, you possibly can have a look at the official docs right here. For our easy case, you simply outline the hostname or ip handle of the service you need to proxy to, and what port is needs to be proxied to, after which confer with the upstream title within the location directive.

Hostname Vs. IP Handle

To grasp what a hostname is, let’s make an instance. Say you might be on your own home community You then arrange a server on and run Plex on it. Now you can entry Plex on, so long as you might be nonetheless on the identical community. One other risk is to provide the server a hostname. On this case we’ll give it the hostname plex. Now you possibly can entry Plex by coming into plex:32400 in your browser!

This similar idea was launched to docker-compose in model 3. In the event you have a look at the docker-compose file earlier on this article, you’ll discover that I gave it a hostname: reverse directive. Now all different containers can entry my reverse proxy by its hostname. One factor that’s essential to notice, is that the service title must be the identical because the hostname. That is one thing that the creators of docker-compose selected to impose.

One other actually vital factor to recollect, is that by default docker containers are placed on their very own community. Which means you received’t be capable of entry your container by it’s hostname, in case you’re sitting in your laptop computer in your host community. It is just the containers which might be capable of entry one another via their hostname.

So to sum it up and make it actually clear. In your docker-compose file, add the hostname directive to your providers. More often than not your containers will get a brand new IP each time you restart the container, so referring to it by way of hostname, means it doesn’t matter what IP your container is getting.

Websites-available & Websites-enabled

Why are we creating the sites-available and sites-enabled directories? This isn’t one thing of my creation. In the event you set up Nginx on a server, you will notice that it comes with these folders. Nevertheless as a result of Docker is constructed with microservices in thoughts, the place one container ought to solely ever do one factor, these folders are omitted within the container. We’re recreating them once more, due to how we’re utilizing the container.

And sure, you can undoubtedly simply make a sites-enabled folder, or instantly host your configuration recordsdata in conf.d. Doing it this manner, lets you have passive configuration laying round. Say that you’re doing upkeep, and don’t need to have the service energetic; you merely take away the symbolic hyperlink, and put it again while you need the service energetic once more.

Symbolic Hyperlinks

Symbolic hyperlinks are a really highly effective characteristic of the working system. I had personally by no means used them earlier than establishing an Nginx server, however since then I’ve been utilizing them in all places I can. Say you might be engaged on 5 totally different tasks, however all these tasks use the identical file indirectly. You possibly can both copy the file into each venture, and confer with it instantly, or you possibly can place the file in a single place, and in these 5 tasks make symlinks to that file.

This provides two benefits: you’re taking up four occasions much less house than you in any other case would have, after which probably the most highly effective of all of them; change the file in a single place, and it adjustments in all 5 tasks without delay! This was a little bit of a sidestep, however I believe it’s price mentioning.

Securing Nginx Proxy

What to Do

Go to your config folder, and create Three recordsdata: ssl.conf frequent.conf common_location.conf. Fill them with the next enter:

Now open the plex.conf file, and alter it to the next (discover traces 2, 6, 9, 10 & 14):

Now return to the foundation of your config folder, and run the next command:

openssl dhparam -out dhparams.pem 4096

This can take a very long time to finish, even as much as an hour in some circumstances.

In the event you adopted my article on getting a LetsEncrypt SSL Certificates, your certificates needs to be positioned in </path/to/your/letsencrypt/config>/and so on/letsencrypt/dwell/<area>/ .

After I helped a pal set this up on his system, we bumped into some issues the place it couldn’t open the recordsdata after they have been positioned in that listing. Most probably the reason for some permissions issues. The simple resolution to that is to make an SSL listing, like </path/to/your/nginx/config>/certs, after which mount that to the Nginx container’s /and so on/ssl/non-public folder. Within the newly created folder, you need to then make symbolic hyperlinks, to the certs in your LetsEncrypt’s config folder.

When the openssl command is completed operating, you need to run the docker exec <container-name> nginx -t to ensure that all of the syntax is right, after which reload it by operating docker exec <container-name> nginx -s reload. At this level all the things needs to be operating, and also you now have a working and completely safe reverse proxy!

Why it Works

Trying within the plex.conf file, there is just one main change, and that’s what port the reverse proxy is listening on, and telling it that it’s an ssl connection. Then there are Three locations the place we’re together with the three different recordsdata we made. Whereas SSL is form of safe by itself, these different recordsdata make it much more safe. Nevertheless if for some cause you don’t need to embrace these recordsdata, it is advisable to transfer the ssl-certificate and ssl-certificate-key contained in the .conf file. These are required to have, to ensure that an HTTPS connection to work.


Trying within the frequent.conf file, we add four totally different headers. Headers are one thing that the server sends to the browser on each response. These headers inform the browser to behave a sure approach, and it’s then as much as the browser to implement these headers.

Strict-Transport-Safety (HSTS)

This header tells the browser that connections needs to be revamped HTTPS. When this header has been added, the browser received’t allow you to make plain HTTP connection to the server, making certain that every one communication is safe.


When specifying this header, you might be specifying whether or not or not different websites can embed your content material into their websites. This will help keep away from clickjacking assaults.

X-Content material-Sort-Choices

Say you may have a web site the place customers can add recordsdata. There’s not sufficient validation on the recordsdata, so a person efficiently uploads a php file to the server, the place the server is anticipating a picture to be uploaded. The attacker could then be capable of entry the uploaded file. Now the server responds with a picture, nonetheless the file’s MIME-type is textual content/plain. The browser will ‘sniff’ the file, after which render the php script, permitting the attacker to do RCE (Distant Code Execution).

With this header set to ‘nosniff’, the browser won’t have a look at the file, and easily render it as regardless of the server tells the browser that it’s.


Whereas this header was extra obligatory in older browsers, it’s really easy so as to add that you simply may as effectively. Some XSS (Cross-site Scripting) assaults may be very clever, whereas some are very rudimentary. This header will inform browsers to scan for the easy vulnerabilities and block them.



As a result of your servers are behind a reverse proxy, in case you attempt to have a look at the requesting IP, you’ll all the time see the IP of the reverse proxy. This header is added so you possibly can see which IP is definitely requesting your service.


Typically a customers request will undergo a number of purchasers earlier than it reaches your server. This header consists of an array of all these purchasers.


This header will present what protocol is getting used between shopper and server.


This ensures that it’s potential to do a reverse DNS lookup on the area title. It’s used when the server_name directive is totally different than what you might be proxying to.


Reveals what the actual host of the request is as an alternative of the reverse proxy.


Helps determine what port the shopper requested the server on.


SSL is a large matter in and of itself, and too large to start out explaining on this article. There are various nice tutorials on the market on how SSL handshakes work, and so forth. If you wish to look into this particular file, I recommend trying on the protocols and ciphers getting used, and what distinction they make.

Redirecting HTTP to HTTPS

The observant ones have possibly observed that we’re solely ever listening on port 443 on this safe model. This might imply that anybody attempting to entry the positioning by way of https://* would get via, however attempting to attach via http://* would simply get an error. Fortunately there’s a very easy repair to this. Make a file with the next contents:

Now simply ensure that it seems in your sites-enabled folder, and while you’ve reloaded the Nginx course of within the container, all requests to port 80 can be redirected to port 443 (HTTPS).

Last Ideas

Now that your web site is up and operating, you possibly can head over to SSL Labs and run a take a look at to see how safe your web site is. On the time of scripting this, you need to get an ideal rating. Nevertheless there’s a large factor to note about that.

There’ll all the time be a steadiness between safety and comfort. On this case the weights are closely on the facet of safety. In the event you run the take a look at on SSL Labs and scroll down, you will notice there are a number of units that received’t be capable of join along with your web site, as a result of they don’t assist new requirements.

So have this in thoughts if you find yourself setting this up. Proper now I’m simply operating a server at dwelling, the place I don’t have to fret about that many individuals with the ability to entry it. However in case you do a scan on Fb, you’ll see they received’t have as nice a rating, nonetheless their web site may be accessed by extra units.

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