I'm currently looking at options to allow me to build a remote COM-port solution.
The idea is to be able to access from my remote PC, another PC that's directly connected to a device locally via its serial COM-port.
I know that the obivous answer is to use a VPN between the 2 Internet connected PCs.
However, I need this solution to be as seamless to the end-user as possible.
i.e. no installing and configuring VPN software, etc.
So I was thinking that WebRTC would be great because the end-user can simply use their web-browser and not have to install any additional software.
My question is, is it possible to stream the COM port data between the 2 PCs via WebRTC?
If so, can you please point me in the right direction as to how I can go about achieving this?
Sorry if this is a ridiculous question, I'm very new to WebRTC, just exploring my options.
Thanks.
That should work great!
Networking wise you get NAT Traversal. That means the two computers can be in completely different networks, and still communicate. You may have to run a TURN server if P2P isn't possible.
Data wise you can exchange anything you want via data channels. It is datagram based and you can send/receive binary data. You get a callback telling you how much has been delivered, that way you can detect backpressure.
Are you ok with installing software on the remote host? You can do something like Pion WebRTC's data-channels. This shows you can have a browser connect to a Go process via WebRTC. Then use tarm/serial on the remote host to interact with the device.
If you want a browser on both ends there is the Web Serial API I haven't used it myself though. That locks you into only doing Chromium which might be an issue.
Is there a better tool than WireShark to sniff out where given application is trying to connect and at which port. (So that I could easily overwrite it with my HOSTS file). Being able to log packet data is helpful too.
Ultimately I would prefer an application that I could just throw a running process at and start logging the network activities of the given app
Of course the application and sniffer will be running on the same PC. Preferably I would love a Windows sniffer. Since running that app on Linux will be .... difficult.
Answering myself: http://www.sysprobs.com/monitor-network-traffic-windows-7-microsoft-network-monitor-34
This article helped me big time. The tool in there is really great.
Have you tried socket sniff?
It should let you monitor specific applications:
socket sniff
I'm experimenting with my Arduino Mega. I also have an Arduino Ethernet Shield.
I need to send emails using them, without the help of a computer (or any other device; like a smartphone, etc.). Though I could find several articles, I couldn't find any acceptable solution...
How can I do it? As I'm not asking this to be used for any special application, you can
make any assumption about missing details.
From the discussion above in comments it sounds like you either need code from someone who has just done it for you or you need to take the time to learn about the components and find or make the components.
They wouldn't make an Ethernet shield for this platform if it was only useful for non-standard packets. So someone somewhere has created some level of an IP stack.
Backing up though, in order to send mail you need to learn the Simple Mail Transfer Protocol (SMTP). Almost all Internet protocol definitions are defined using something called RFCs (Request for Comments). So if you google SMTP RFC you will find RFC 2821.
IETF is Internet engineering task force. There will be many copies of these documents on many websites. And due to the age of the Internet and these protocols in many cases you will find that one RFC has been created to replace a prior one. Version numbers are not used, but it is kind of like HTML 1.0 then HTML 2.0 and so on. I recommend even though the RFC says that it completely replaces RFC xyz, go find RFC xyz and read it. I go back as far as I can find learn that one then work my way forward.
Many/most protocols that ride on top of TCP (TCP is yet another protocol defined in an RFC, more on that later) are ASCII based, makes it very easy to, for example, Telnet to learn/experiment with the protocol, you can probably use Telnet to learn SMTP.
Most protocols are some sort of a half duplex thing, make a connection and often the server sends you a string, you see that string and then you send some sort of hello string, the server responds with some sort of OKAY or fail status. For SMTP, you then do some sort of I am mailing from this email address, server says OKAY, you say I want to mail this person or this list of people, for each email address you get an okay or fail. Eventually, you tell the server you are ready to send the body of the message, you do that, end the message with the defined termination. Then either the server says okay or fail or maybe there is some more handshaking.
The protocols in general though have this back and forth. Usually you are sending strings with commands and usually the server side sends back a short okay or error. Sometimes, if they want, they send back more detail on the error, but always start with the few bytes that indicate okay or error. The protocols generally have a flow, you must do this first then this then that.
You should learn sockets programming, sometimes called Berkeley sockets. You can write programs that are mostly portable across unixes but also across to Windows using Windows sockets if that is your platform of choice. You need to learn the protocol first, and it is better on your desktop/laptop and not embedded, you can get it done faster there. You do NOT have to learn to fork or thread to use sockets. The examples may show that as it is easy to show it that way, but you can write complete applications using polling only, it is half duplex send something, wait, send something, wait. For these simple learning programs, a little time up front to learn sockets, from there, it is all learning the protocols.
Now that was the very easy part, the hard part is the TCP/IP stack. I do not recommend attempting that without gaining a lot more experience taking baby steps on your way there. For example, learn to respond to ARP first (yet another RFC protocol, address resolution protocol) then ping (ICMP echo, one subset of the ICMP protocols) then IP basics (sniffing packets) then receive and generate UDP packets. TCP is a whole other level above that, more handshaking. It is not fixed packet size, it is streaming, do not have your code operate on packets, it is a stream of bytes, like working with a serial port.
Doing your own TCP stack is very much a non-trivial thing, I don't recommend it, you need to find someone that has done a TCP/IP stack for this platform for the Ethernet shield and just use it, whatever RTOS or environment they use, use it. Then take your desktop/laptop based experience with the protocol and apply that.
From the discussion above, if you don't want to learn the protocols, etc., I think you need to google around looking at Arduino Ethernet shield examples and see if anyone has done something that sends emails.
So when I am debugging my web applications and such, I've used the Charles web proxy and debugger and love it. It's so nice to see what's being sent and received via port 80 and 443. I can see all the resources loading, not just from the "browser" per say, but also flash applications. I can also see how the calls are being made, and it pretty easy to reconstruct them. It's a great debugging tool and I love it.
So I'm wondering two things:
First, I'm wondering is if there is something similar I can use to watch traffic that might be coming though on other ports. I guess some desktop applications will use the internet, but not necessarily via http / https requests. I remember looking at some security tools a few years ago - there are a lot of security tools out there, like kismet / etherCap, ethershark, etc - is there one that does what I'm describing in an easy and intuitive way?
Also, I'm wondering if I am using my iPhone / iPad / Android device, how can I set up a proxy through my computer so I can watch the http/https requests that the device makes?
Found the answer to that one here: http://www.ravelrumba.com/blog/ipad-http-debugging/
I'm mostly on a Mac so anything that is Mac friendly would be extra helpful.
Thanks!
I believe you are looking for Wireshark. It allows you to monitor the network interface on your machine and be able to tell you sent/receive packets as well as their protocols. It also has a protocol decoder that can be used to get Layer 7 information about a IP stream. You can also do a "Follow TCP stream" which allows you to view the entire conversation of that connection. It's based on libpcap (Packet capture) which the built in tcpdump also uses.
The only downside for you web developers is that if you're using SSL encrypted sessions, you can't decode it. The endpoints of the SSL session are "above" (using OSI model) the layer at which wireshark (and similar tools) operate.
Here's a good list http://sectools.org/sniffers.html. I used Wireshark back when it was Ethereal. At that time it ran under X11, It looks like that has changed.
I want to see what a application send to network and if is possible to edit or stop them. thanks ;)
I would definitely recommend WireShark. But be careful, if this is a corporate network you will need permission. Sniffing traffic can sometimes be cause for instant termination, so get it in writing!
Changing and editing traffic are much more complex tasks. That answer really depends on what you want to do.