I open IE explorer & Chrome in my computer and type localhost:80 and I get the index page.
Here I think my machine's IP is same to both connections (IE explorer & Chrome) and ports are too (80).
Note: Source port will be different (as destination is same: localhost IP), this is my second question.
So how webserver (lets say apache) handles this port 80 connections without failing? Does it port forwarding? In OS level even I tried with addr re-use, port re-use parameters and it is all same we cannot make multiple connection with same IPs & ports.
Now, probably you have came up with a solution: although source ports and IPs are same, destination port is different in package: <protocol>, <src addr>, <src port>, <dest addr>, <dest port>.
A. I got 49483~50004 ports as you can see on image. How client knows which destination port (49483~50004) is bound by webserver? If it is random between 0 and 65355 the webserver always binds all ports, it is very resource consuming. How webservers avoid from this?
Look at this image: command prompt-> netstat
If this question is related with low level sources it is OK, I understand Embedded TCP/IP/UDP, Phy MAC communication and package structures.
You have this all back to front.
All the port numbers at the server are the same: 80. So the client only has to know port 80.
All the port numbers at the client are different: 49483-50004 etc. So there is no ambiguity in the connection, because the 4-tuple you mentioned is unique.
All http request by default call to servers in the port 80, because servers listen by default in that port. So you only give an IP or hostname and the web browser add the default port (80). You can give a custom port if you web server is listenning in another port (usually Tomcat listen by default in 8080) for example you call it in: http://www.youamazingweb.com:8080.
A good example is see the IP as the home and the port is the door where clients enter to consume some resource hosted in server.
Related
I have a java program that uses SQL queries. The goal is to send them from my home PC to a workstation on a different network elsewhere.
The SQL server is on Windows Server and I opened port 1433 for inbound connections. From that computer, I can successfully ping the port. However, I can't ping the port from the public ip address, only the local (192.168...), so it doesn't work if I were to try to ping it from my home computer.
Is there a way that I can ping it from my home computer? If so, how would I specify the address for JDBC?
Thanks!
It sounds like your Windows Server is behind an internet gateway/router. You need to configure the gateway to allow and forward inbound connections to TCP port 1433 to the IP of the computer that has SQL Server installed.
Here are some guides that explain how to enable port forwarding on different devices:
How to Forward Ports on Your Router (lifewire.com)
How to Port Forward (No-IP.com)
Also, note that we can ping IP addresses, not ports.
I don't have a ton of experience with routers or port forwarding, but I do have a new Raspberry Pi and I wanted to see if I could set up a simple Hello World page just for educational purposes. I have quite a bit set up with apache2 already installed and the web page works great on my local area network, however I can't connect to it using my LTE from my phone, telling me this thing does not connect to the internet.
I am currently using Rasbian under all the default settings from the pi.
My router is an all in one modem and router, from xfinity. After sifting through countless sites trying to solve this issue, the following 2 were the closest thing to my particular issue. My reputation is not high enough to put more than 2 links, so I will put the most important ones..
So to the best of my knowledge this is the way to do it ...
1) Set the web server up to work locally
2) Then go into the router with the IPv4 or IPv6 (shouldn't matter which) and forward all Port 80 traffic to, say, Port 8080 where my PI 'should' be listening, then send back my web page down through Port 80 to the client calling the web page.
Under 10.0.0.1 I find this...
Then I go to 'Advanced'
I have tried from Start port 80 to End port 8080, which my 2 PI files I edited to listen for that port.
Those files are under
sudo nano /ect/apache2/sites-enabled-000-default.conf
and
sudo nano /ect/apache2/ports.conf
I changed
Listen 80
to
Listen 8080
and all other combinations alongside changing my router Start and End ports... none of which worked so I am lead to believe there is either a knowledge gap or I am doing something terribly wrong.
I just want to put a simply Raspberry pi web server online from my Local connection at home using a Comcast xfinity router. If anyone has any experience doing, I would seriously appreciate it, I've spent far too many hours trying to walk through this alone, so now I am reaching out to the faithful stackoverflow community.
It sounds like you are almost there.
For you to be able to access your raspberry pi server from the internet, you need to find your external ip address. Your router has one external ip address that you can reach from the internet. While on your wifi, search google for "what is my ip" Google may display it as the top result, or you might have to click into a site like ipchicken. Write this IP address down.
Next, setup your router to forward all port 80 (default http port). Try setting Apache to listen on port 80, and have your router set with start port and end port to be port 80 (this makes it so you don't have to put :port-number in the address, i.e. you will do http://your-ip-address rather than http://your-ip-address:8080). The start port is the port on the external network, the end is the port that your Apache server is running on the raspi.
It looks like your raspi has the ip address of 10.0.0.17 on your local network based on your screen shot. If it doesn't, change the IP address in the port forwarding section of the router configuration to be the IP address of your pi. You can figure out what the assigned IP address of your pi is through the router interface, or by typing ifconfig -a and looking for the ip address of the adapter that you're using to connect to the network. Your router may have the ability to assign a static ip address to your raspberry pi while it's connected to your network. It would say something like DHCP reservation. You'd need to find the MAC address of your pi. You can do that with ifconfig -a as well. Then configure your modem to always assign your pi the same ip address that you've configured in the port forwarding.
Now that everything is setup, switch to your cellular connection and then try to go to the ipaddress that Google gave you.
type your-ip in browser address bar -> port 80 request to your modem's IP -> you've set external port 80 requests to be forwarded to port 80 on your internal network for the device 10.0.0.17 -> your raspberry pi will serve the HTML
Note: The external ip address of your modem is most likely not static unless you specifically pay for a static address. This address usually will stay the same for at least a day though, so if you're just testing, it's not a big problem. In the future, if you want to ensure that you'll be able to reach your pi, look into dynamic dns.
The Apache webserver uses port 80 to listen for incoming requests and replies over port 80. Firefox uses port 80 to send requests to webservers and then listens on port 80 for the response from the webserver. I have run Apache and Firefox simultaneously before and am just wondering how two different programs can share the same port.
Each side of a TCP network connection is defined by a touple of (ipaddress, port #). When a packet leaves your system all it knows is that it needs to find ip address 192.168.1.1 and go the whoever has a socket bound to port 80.
A server socket is going to be defined by the address on which Apache is listening and port 80. The client socket open by Firefox will have the same ip address but a different randomly assign port number which you normally do not see.
You can see it using netstat or tcpview (Windows)
For example when I run netstat right now I see:
tcp4 0 0 x.x.x.x.62993 stackoverflow.co.https ESTABLISHED
where x.x.x.x is my laptops ip address and 62993 is the random port number assigned to my web browser.
Firefox isn't listening to port 80. It's making a request to a server port and handling the response.
I am looking for a program to reroute windows domain resolution lookup through a socks proxy capable with many internet browsers and internet proxies.
So far in Control Panel, Local Area Connection 1, TCP/IP Properties, I use the following DNS server addresses, preferred DNS Server, I put 127.0.0.1 and use the default in-built port request 53.
I am reading that it is possible to forward this. I can not find a program to forward it through socks 4/5. I think this is possible because Socks supports UDP.
Has anyone come up with the answer to a solution about a UDP-to-socks forwarding program capable and adapted for socks and windows DNS.
It's really quite easy to configure.
You could write your own server and set the server to listen to incoming calls to port 53 or use this program
http://dns2socks.sourceforge.net
here my sample configuration for a socks server running on 1050 and TCP / IP settings on 127.0.0.1
DNS2SOCKS.exe /la:socks.log 127.0.0.1:1050 8.8.8.8:53 127.0.0.1:53
For such a program you can have a look at dnsadblock. Their free daemon/cli app opens up a proxy server that can be configured to use a proxy/socks to communicate with the upstream server. It works since the remote endpoint listens on https which makes DOH (dns over https) possible. Config options/install instructions: https://knowledgebase.dnsadblock.com/how-to-install-and-configure-our-software/
I have to set up a Virtual Machine on vBox that works as a server for my app. Now, the app sends data to http://x.y.w.z:4567. I run apache server on host and wireshark confirms that the packet is received. Guest is behind NAT and is set up to forward TCPs from any IP port 4567 to port 443 on guest. I tried various versions of setting and not setting IP. Guest also has apache running, but it receives no packets. What should I do?
Please check the log that your port-forward rule is active. Also that your guest/host firewalls doesn't drop packets.