at my firm we have a jupyterhub/lab installed and is used by roughly 70-100 people in a secure network that can only be accessed to from work. Recently the idea of hosting web-applications for short time use came up, but we are having port problems. User A is running a web application on port 5000, and User B can’t use the port because it is already in use. Port 5000 is default, it can be changed but this is not the behavior we want. Does anyone know of a way for web-applications to run on the same port in the same environment? Have looked into server-proxy but i do not really understand it. Is the way to achieve this really to be running a vm for each user securing that the port is not in use?
Any help is appreciated
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I have been asked to take over a project where the previous developer had used socketio4net,
hence I learnt of the socketio4 project only now.
the problem my employer is facing is clients having proxy servers.
we have installed our product(client side) on clinics which uses socketio4net and websocket.
They all connect to our main azure server for sending data. In clinics without proxy,we are not facing any issues. but those with proxy server, our service is not even starting.
if we have to implement the ssl process, it will be a big overhead for us
how do we achieve ssl and proxy settings for sockets in general? does socketio4net provide any other options?
do I have change to http classes like webclient?
In my experience with proxies and school's in particular, the vast majority turned out to be a firewall based issue.
What port are you using, 80, 443 or something else? If that is the issue, the clinics would need to either whitelist your server ip, or allow the ip:port combo you've set.
For a quick test at the clinics that have issues - I would try these two sites (probably others sites you can find too):
http://websocketstest.com/ - tests for ports 80, 8080, 443 with and without ssl - do all or only some work?
(this site is also great for a end-user at the site to run for you, as you can get a results link - double bonus points!)
http://www.websocket.org/echo.html
Are both of the sites above able to connect?
Hope that helps...
forgive the triviality of my question. I was asked this question and I wasn't able to find a proper answer so I decided to research this myself and understand. I have spring ,maven etc background. Supposing I deployed my web app on a box 192.168.0.10 in my network, can I listen on the port say 9090 of the 192.168.0.10 and do something with it in my application itself running on tomcat7 on the usual port 8080.
What all this is supposed to do is listen on a port and display a graph on the client side based on the value received.
I was thinking using maven, I will have a jar packaged project handling the networking bit and transfer the control to the web app.Event that it's really blur in my mind.
Can anyone clarify things a little bit for me?
Thanks in advance
Why do you need a different port, effectively your web app is already callable on the port provided by tomcat. You can have various servlets each distinguished by URL, and one can return graphs. There's lots more possibilities, but I don't see any need for another port.
I want to develop an iPhone app with a simple IM feature. I am thinking about setting up an HTTP server on an iPhone. If the iPhone is using wifi and is behind a firewall, how can I make sure that other iPhone clients can connect to it?
It's not the firewall that will disturb the connection as much it is the NAT.
When you are connected through wireless router to connect the internet you are surfing via NAT. it means you dont really have an extenral IP but once you initiate connection the router will map your intenral IP to one of his externatl ports and for certain time window he will pass connections to you if he will get it to the right port.
That being said, there is no actual way of setting a server behind a NAT unless you can configure port forwarding in the router and internal static IP.
Hope i was clear enough, good luck
I do not really think that you need to get an HTPP server up and running on iPhone to make an application that can send and receive messages (IM). The idea of making one iPhone user to directly connect to one another does not seem right to me since the users will need to know IP addresses of one another to do that.
Interconnectivity between different users of the chat can be solved by making your application communicate via a dedicated TCP port. It is generally advisable to choose ports with a number higher than 1024 since those below are generally found on the list of so-called well-known ports and are used for Web (like port 80), FTP (port 21), SSH (22), DNS (53), etc., it will be the responsibility of the user to make sure the port used by your application is open on the firewall. In order to solve this problem you can actually use port 80 for communication if you find that the port you have selected is blocked. You can do this because you know that this port will not be blocked in most cases. Indeed Yahoo Messenger is reported to use this technique when the firewall blocks the port it uses for communication.
The port should be used by your application to connect to the Web-server that will actually store user credentials, perform authentication, message transmission, etc., and the server should reside on capable hardware to be able to support large number of simultaneous connections. I can suggest using either a VPS (like the one provided by Linode) or a cloud (like Amazon EC2, Google Application Engine, Rackspace).
I do know that I can't have two programs listening to the same port, but I am wondering if it is possible to fake it somehow, for an example:
My machine has two applications, one listening to port 80 and the other to port 6653.
If I get an incoming connection, let's say mysite.com:80/chat then it would be forwarded internally to the application listening on port 6653 and the data returned from that server would be forwarded back to port 80 somehow.
The reason I want to accomplish this is because there are many firewalls that seem to block connections to ports other than 80.
I have a chat server that I want to run on port 80, perhaps I could get another IP and machine for that, but it feels like too much trouble for a single chat server.
Any helpful feedback would be appreciated. Thanks!
You can probably do this with mod_rewrite if you're running Apache. That link has plenty of examples, including what you want (I think).
EDIT: I see you've updated the tags to say "asp.net". I'm guessing that you're not running Apache, then. I'm sure there is a similar tool for IIS, or you can use a proxy server that does the same thing.
There is a module called URL Rewrite that you can install on Windows Server 2008 (and R2) that is functionally the same as Mod_Rewrite. Download it here: http://www.iis.net/download/URLRewrite
I have an iPhone app which relies on connecting via the local network to a server running on a user's mac/pc.
The server is running an http service on port 8080
I already add exceptions to the default windows firewall, or the default mac firewall to ensure traffic is allowed to reach my app.
However the most common customer issue is that the iPhone can't communicate with the server.
Normally this is the network router blocking traffic - though sometimes the user is running their own firewall which blocks the traffic.
Is there a protocol which will let me say something to the effect of
'will all the firewalls on this network, please allow communication to <an ip> on <a port> if the traffic originates within this network?'
I have looked into upnp - but that seems to concentrate on opening a port to the outside world which I don't want to do.
suggestions?
thanks in advance.
No, there is no such way or protocol aside from UPnP. And I wouldn't recommend it anyway because in company networks it would cause all sorts of problems and security issues if this were possible.
I'd suggest that you set up a FAQ entry or installation section for your software where you describe this common issue and give details to the customers how they can detect and solve this problem.
In general, higher ports (above 8000 or 16000) are not blocked or firewalled. I would seriously consider allocating a random port in that range.
Also, consider to advertise your service with Bonjour. Using Bonjour has the nice side-effect that your iPhone app does not have to know the port number. It can simply browse the network for available servers. If there is just one then connect to that, otherwise present the user with a list to choose.
Is there any way to run the server on port 80? You're likely to encounter fewer issues on a standard port.