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
Related
I need to write my first socket program involving TCP connections. In the program I have created there is a client and server, both of which are the machine I am coding on.However,it requires that I pass the port number as a command line argument. How do I accomplish this?
The answer is simple : Make sure your server and your client agree on the port to use. As long as the port is available and can be used, set up the connected so that the client and server use that same port.
Here's a link that explain the different ranges available for TCP and UDP ports.
As an exemple, the port 3074 is used by microsoft for its Xbox live service. Making an application using this port might interfere with the service.
The port used will be defined either in a configuration file or hard-coded in the source code of both the server and the client. You should easily be able to find it with a quick look at the code or the directory which contains the application.
Im just wondering, can 2 or more different external hostname/DNS redirect to multiple local servers but same port?
Let's see, I have 2 DNS internet domain for an example, myserver1.com and myserver2.com, and both I have same A record to my forwarded server IP (e.g: 102.123.123.123). Under my server which only has 102.123.123.123 IP address has 2 application servers but instead of trying to make they work, I use different port for each server applications for an example, serverApp1 listening to 0.0.0.0:2010, serverApp2 listening to 0.0.0.0:2020
My point is, is there any way or how to forward my myserver1.com:2000 to serverApp1 (port 2010), and myserver2.com:2000 to serverApp2 (port 2020) but both myserver1.com and myserver2.com has a same A record?
Im quite sure either it is in iptables or /etc/hosts or BIND issues, but guide me if I missed something. And by the way, the servers and DNS records are accessible from the internet which is the firewalls are configured properly. Thanks.
I don't have much experience in that, but I think you will need a third server/firewall/proxy listening for the incoming host and route it accordingly.
Again, I don't have much experience in that, so I'm not sure if the firewall is able to do that.
I think you can use redirection servers like apache.
In my application we want to access lot of intranet servers from internet. So what we did, we configured a apache with all the mappings in httpd.
So when ever a request to apache comes, it will be redirected appropriately.
For example - I have two servers or hostname in intranet : 1) abc.com:7300/context1
2) xyz.com:8900/context2
We configured a apache with host name abcxyz.com:9000. When a request like
abcxyz.com:9000/context1 comes it will be redirected to abc.com:7300/context1 and when a request like abcxyz.com:9000/context2 comes it will be redirected to xyz.com:8900/context2.
In your case since the requests are going through the single server (102.123.123.123), you can use redirection.
Hope it helps.
Just curious. When developing with Casini development server, one has an infinite number of ports. But, the production servers seem to give a particular importance to port 80.
Has that to do with a technical requirement, a convention, or both? I've checked the web but haven't been able to find a clear response so far.
Thanks for helping.
Many services have specifically-assigned ports This allows users to type, for example http://stackoverflow.com and get the website for SO, without needing to enter a port as well. This isn't a technical requirement; however, using a different port requires the user to know an extra piece of information, which must be entered into the URL every time.
When you connect to a server via TCP/IP you specify particular port you connect to. You do not connect to a server and hope that server guesses which port you would like to talk to.
So in most cases you tell browser to use protocol http, say "http://example.com/" then browser uses default port number assigned to that protocol (http) to connect to server "example.com". In this case port is 80. If for example you specify "https://example.com/" then browser looks for default port for https and then connects to port 443 instead.
So if you do not want to tell to every of your users to specify some non-default port for your service (say "http://example.com:60765/") you better use default one.
BTW there is a way to get port number your service listens to by it's protocol name (by asking a service's host's daemon at port 0) but this method seems to be rarely used (if at all).
See also other answers: default protocol numbers are assigned by IANA
It's a convention: you can use whatever port you feel like. You can look at the evolution of RFCs to see when the convention was official (http://www.faqs.org/rfcs/rfc1700.html)
You can see in the RFC 1060 (http://www.faqs.org/rfcs/rfc1060.html ) that it's the ISO Internet Protocol :)
In a production environment your web server is embedded in a server infrastructure (firewalls, proxies) protecting you against attacks from the internet. In such an environment port 80 is normally open for HTTP traffic. If you use this port there is no need to configure your server infrastructure.
I'm trying to take advantage of HTML 5 web sockets in .NET and the easiest way appears to be something like what this guy does.
I've already tested this myself and it works great, but there are a few problems if I try to deploy this to my hosting site (discountasp.net). Basically, I am not allowed to open up a port on 8080 and listen on it. I then tried to figure out a way to listen on port 80 with IIS as well, but using the HTTPListener, I run into sercurity issues as well. This doesn't seem like it will help since I can't mess with this stuff on the hosting site server either.
So to make my life easier, I think I need to find a hosting site that simply allows me to open up a socket on port 8080 and listen on it. Anyone know of one? Or does anyone know of a workaround (besides sniffing all the traffic on port 80)?
We have a asp.net 3.5 web application running on a hosting company's web server that's got a very strict firewall setup. The web application communicates with our sql server express 2005 which is on a completely different network.
The problem is that the web applications sends our sql server a random port number to connect to when it connects to our sql server on port 1433. Hence the web application can not connect to our sql server because then they have to open a whole range off port numbers on the firewall which they are not prepared to do.
My question is the following. Can you specify either in your connection string or somewhere in your web.config the port the client sends to sql server to connect back to on?
Thanks
If I'm getting you right, you want to do something that goes against how TCP/IP port handling is supposed to work.
You want the web application to always use the same port when connecting to your SQL server? This would mean you can only have one connection open at any given time, and so only one user at any given time. The client is supposed to communicate with a server from a "random" port. It's the basics of networking. At least how I learned it.
I'm not sure you can even force it to use the same port every time, and even if you can I'd advice against it.
I'd say the problem is the firewall, and not your application. I can understand that the SQL server only wants to speak to the IP address that your site is on, but it shouldn't really care which port the client wants to talk over (something like [website-ip]:* -> [sql-ip]:1433). To me, it seems like who ever set up the firewall has some kind of crazy firewall ideas, but maybe that's just me.
Is it possible that your SQL Server Express is configured to listen on dynamic ports? If the 'TCP Dynamic Ports' value is 0, I think it will be dynamic even if you have a specific port configured. That value should be cleared completely.
You can specify port if you are using TCP/IP.
For ex:
Data Source=190.190.200.100,1433;Network Library=DBMSSOCN;Initial Catalog=myDataBase;User ID=myUsername;Password=myPassword;
where DBMSSOCN=TCP/IP