I have set up a mosquitto-broker on my raspberry pi which I have running on my local network. I've tested this locally using the paho-mqtt package in python which is working, however I want to access this broker remotely (outside my local network).
From what I understand, the safest way to do this is to use TLS-authentication and configure mosquitto to listen on port 8883, rather than opening the un-encrypted 1883 port, where login credentials can be sniffed. This is where my problems start, as I suspect my ISP doesn't allow forwarding port 8883 to the (static) IP-address of my RPi. (Port wont open no matter what I try, and I've tried googling this specific issue.)
So my question is:
Is it possible to use another port than the default 1883 or 8883 (which my ISP hopefully allows to be opened) for accessing my locally hosted mosquitto-broker? For example one of the higher-valued ports, which I understand is not reserved for anything.
I'm imagining connecting to the broker by using my external IP-address with this port (xxx.xxx.xxx.xxx:yyyyy) and either tunneling this data to the 8883-port on the local network, or configuring mosquitto to listen on the selected port. Any tips on how I can solve this issue?
EDIT
Thanks for your answers! I just got off the phone with my ISP, and unfortunately they don't allow opening ANY ports because I live in a university dorm, so opening a different port won't work either. I guess using a cloud broker is the only option.
You can use any ports you want (or that your operating system will permit). MQTT uses certain ports by convention but is not restricted to using those ports. You're even welcome to encrypt on port 1883 if you want.
You'll need to do four things:
write the listener configuration directive correctly to use the port you want to use and make sure that you're listening on 0.0.0.0 in order to listen on all network interfaces, or the IP address of a specific network interface to listen on.
correctly configure encryption after the listener directive
ensure that the port you chose is accessible through any firewall your server may be running
properly configure any clients to use the port you configured and work with the encryption you configured
If you want to make it accessible over the Internet you'll need to open a port on your router as well.
If you do make it accessible over the Internet, please require authentication. Encryption won't stop strangers from connecting to your broker, it will just stop eavesdropping on them. Turn off allow_anonymous and set up some Mosquitto accounts.
Related
I am using (airtel xstream fiber) connection and trying to do port forwarding. I forwarded port 3000 of wan and direct it to my system ip address 192.168.1.2 on port 3001.
Node server is running on my system on port 3001. And I can access my hello world website locally using 192.168.1.2:3001. But when I am trying to access using public ip, it show this error code "ERR_CONNECTION_TIMED_OUT".
Also, I found my router port 3001 is open using online port checking tool/website.
So, Can anyone please tell what could be reason behind this ? Is this the problem with windows.
You first need to check what ports are open by your ISP. If your ISP is giving you a local ip at the router. Basically, creating a ppp connection. It may be using a cg nat. In that case you need to buy a static ip, without that none of the traffic will be Directed to your router. Let me know if you find something, I'm currently looking to get xstream airtel as well.
No there is no need for static IP to be access server remotely. As of now, What I see is airtel allocates new ip every 24 hr or when router got disconnected. To access your server remotely you can do two things. First one is more secured.
Change Primary IP adress of your airtel router and use Portforwarding so that its port 80 will be free for you.
Enable DMZ and point it to your local server IP. [192.168.X.X]. In this case all of your ports of the device are exposed to internet. If you want to be secure. Make sure add another router between server and airtel router and enable port forwarding.
But in this case there is a catch, When you try to access your local website using public ip (which you can see on google search) it will redirect you to airtel router panel. But when you try to access it using other device (not server otherwise server will get disconnected) connected to internet using other network(other that your current airtel router like JIO sim, Airtel Sim, etc), It will work excellently.
To get rid of dynamic ip use no-ip services. Its website will help you more. Basically, It is dynamic dns server where you will get free domain. That will get update regularly while its service running on your system. To use other dns provider service like godaddy you must need an static ip.
I know that ipchicken.com will tell you your router's ip address and the port it is using for your connection. But can this information be obtained "locally"? (Without relying on a website).
What I want it for is establishing a connection between two random hosts...without a "dedicated server" in the middle. My problem is to reach through the NAT. I think the best bet is a kind of TCP hole punching, where both hosts connect somewhere and then just tell each other (it can be by phone or chat or similar) the current ip address and the port number their routers are using. It should trick the routers into forwarding the packets to the hosts, albeit coming from a different source than they originally connected to.
Is it possible to find the port number your router is using to patch you through in a more local manner than ipchicken.com?
Are there any ideas on other possible approaches to this problem?
EDIT: Setting port forwarding on the router is not an option in this case, as many people (including me) do not have admin powers over their routers and I do not want to impose such a task on the "users" of my application
The router would use a different source port for every outgoing connection, so checking based on an outgoing connection will not work for your use case.
For an incoming connection, i.e., if you want to reach a specific machine behind a NAT device (like a home router), you'll have to explicitly open up some ports on the router and set up forwarding rules. The router would then listen for incoming connections on that port and forward it to a machine:port based on the configured rule.
How you do this would depend on the specific router make/model. Search the web or logon to the admin interface and look around, it should be easy to find. However make sure you understand the security implications of opening up a port on your router!
UPDATE based on edited question:
Without port-forwarding and if both devices are behind NAT, your only solution is to have an intermediary server! If only one of them is behind NAT, you can have that machine initiate the connection.
You could use a Stun server as the external globally reachable server.
I've been investigating networking for use in a two-player game I'm writing, and I'm still not clear on when a device must have a port forwarded in order to communicate with the outside world.
From what I've seen in other games, port forwarding is always required in order to host a server, but is not required on the client. In addition, there are other situations, such as skype (which, to my understanding is ultimately client to client), where neither end must forward a port.
So my question is, in over-the-Internet communication, when is and isn't port forwarding necessary, and what steps can i take as a developer to make it so my users don't have to worry about it? Thanks in advance!
Port forwarding is needed when a machine on the Internet needs to initiate a connection to a machine that's behind a firewall or NAT router. If the connection is initiated by the machine behind the firewall, the firewall/router automatically recognizes the reply traffic and sends it to the machine that opened the connection.
But if a packet arrives on the external interface, and it's not a part of such a connection, the router needs to know what to do with it. By default, it will reject it. But if forwarding is configured for the port, that tells it what internal machine to send it to.
Put another way: you need port forwarding if you want to run a server behind the NAT firewall/router, you don't need it if you're just running a client.
There is reason why Skype don't (not always) need manual setting of port forwarding:
When you install Skype, a port above 1024 is chosen at random as the
port for incoming connections. You can configure Skype to use a
different port for incoming connections if you wish, but if you do,
you must open the alternative port manually.
If the port chosen for incoming connections becomes unavailable, by
default ports 80 and 443 will be used as alternatives. If another
application (such as Apache HTTP server or IIS) uses these ports, you
can either configure the application to use other ports, or you can
configure Skype to not use these ports.
Port forwarding is must if you host a server.
You can use same technique as Skype...
I am not sure if there is any other option...
Port forwarding (occurs) when a NAT, firewall or some other device blocks communication on all or some ports.
To answer your question as an example, most commercial routers use NAT to allow multiple people to use the same IP(As view from the outside world) provided by ISPs. Most ISP's use NAT to allow multiple customers to use the same IP(As viewed from the outside world). To get this to work, the NAT changes the internal IP and the port number of a communication to THE(there is only one for the entire sub network) external IP and a new port number. By doing this, the router/isp/ect can tell which internal IP and port each external communication goes to.
Anytime one of the computers communicating over the internet are behind a NAT, port forwarding is required. I'm sure there are way more situations than this, and the solution to each can be quite complicated. But this covers the vast majority.
I have a working SSL server implementation, but the problem is that the server is visible only for devices in my local network, and can't be accessed from outside.
Is this a common problem for servers, or have I done something wrong? Could it be my Linux distribution limiting the visibility?
Best regards,
Rat
If you are behind a NAT firewall which most modem/router/switch all-in-one boxes use, then you will need to set up port forwarding on the router.
Port forwarding allows an incoming connection on a port on the WAN side of the modem/router to get forwarded to a LAN computer.
See http://portforward.com/ for help setting up port forwarding.
I don't really understand the differences between the different ports. I couldn't find any useful resources online that would go into detail about it. From what I can understand, it acts as some kind of filter that blocks out any other request not using the same port number.
When will I, if ever, need to change the port number when typing in a website in my browser? What about if I am running my own website? Are there any risks I take when using port 80? As in, are there ways to use different port numbers to hack into a website?
And since a Simple Mail Transfer Protocol uses port 25, could I use this knowledge to send emails using self written programs?
By conventions and standards, defined protocols generally listen on defined ports by default. You can set any service to listen on any port you want, just be aware that changing from a standard port means that standard tools would need to be explicitly told to use your non-standard port.
For example, if you run a web server then by default it's probably listening on port 80. So all someone needs to do to visit your server is use the address:
http://www.yourserver.com
However, if you change it to listen on a non-standard port, such as 81, then any user who wants to visit your site will need to specify the port number:
http://www.yourserver.com:81
The standard convention of just using the address wouldn't be sufficient, because you've broken convention. Now, this is fine if you don't want people randomly using your site and only want it to be available to people to whom you've told the port number. This is called "security through obscurity." It doesn't actually secure your site in any way or filter out anything, it just adds an additional step to the use of the site.
As for SMTP, yes, you can write programs to connect to port 25 on SMTP services and send data to those services. You may indeed be able to spoof emails in this manner. However, most services have other built-in checks and balances to prevent such spoofing.
TCP/IP supports 2^16 ports on a machine. A server program is said to listen on a specific port; other machines contact a server program at a machine using the port number and the name of the machine. It's like the address on a letter.
Some port numbers are "well known", which just means they're officially assigned for a particular service: port 80 is for web servers, port 25 for SMTP, port 25 for telnet, etc.
But any server can run on any port; it's just a matter of changing the code or the configuration. Sometimes you may way to run two separate web servers on one machine; one might listen on port 80, and the second one on some other port (8080 is a common choice for servers used during development.)
So the client can't meaningfully change the port to some random number: there has to be something listening on that port, on that machine, or it doesn't do anything.
There is no 'difference' between running a web server on any port number, from a purely technical perspective, as long as the client and the server both know which port to use. When the client connects to the server, it has to know the IP address as well as the port.
By convention, several ports are used by standard services. For example, port 25 is SMTP, port 80 is the http port, 22 is the ssh port, etc. Because of these conventions, ports less than 1024 are reserved by the operating systems and can only be opened by a root process.
Unless there is a specfiic reason, it is generally a good idea to stick with the standard port numbers. Advanced port scanners/ analysis tools will try all ports on a system, so there isn't much benefit to running a service on a non-standard port.
The port numbers are a way of multiplexing communications over IP links. This is commonly used to provide specific services on accepted port numbers. HTTP servers have been allocated port 80 for listening for incoming client connections, though this is not a lock - there is nothing stopping you constructing/configuring an HTTP server that listens on port 9001, or whatever. If you did use a non-standard port number for your server, then you would have to specifically instruct a browser to connect to that port, rather than defaulting to 80 as it normally does.
SMTP in port 25 using your own program - sure, you can do this. Any mail app is some developers' 'own program' .
Rgds,
Martin