How can I check if my Android application is able to connect to a certain host? For example, I can make a HTTP GET call from a company web service if I am connected to the company network. If I am not on the company network (router, etc.) I can't make the HTTP GET call and it says "Unable to resolve host : No address associated with hostname". How do I check if the wifi or data is within the company?
That error means you don't have an IP related to the domain you want to surf. There is something wrong with DNS.
Try to use nslookup to check your connection with host you want to visit and then check if HTTP GET returns error.
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I am hitting otp api's from Emulator its work but if I am using real device then getting failed to http connecting error found.
2020-11-06 13:33:23.603 24840-24840/a3.amp35.in E/Genrate: failed to connect to /192.168.132.101 (port 80) from /26.81.35.26 (port 39596) after 100000ms
need help
Your device is outside of your local network. Api is on 192.168.132.101 while device is out given net 26.81.35.26
Either expose your API to the outside world (eg. port forward it or host in on globally accessible device) or connect your device to your local network (eg, use the same WIFI, or via VPN)
Also firewall settings on the 192.168.132.101 might block the incoming connections from different subnets.
And probably many more possible causes...
In my project I need to find the public ip address of a machine.
I have implemented that using method mentioned in Finding public ip address using java
I have an api url like 'http://182.14.10.5:8080/test/addVendor' (not exact url) in my project and has been deployed in external tomcat server which has public ip address as 187.15.161.90.
The issue am facing is:
When i tried loading this api url from other devices like mobile or computers belong to some other network, am getting the same ip 182.14.161.90 for every URL hit.
This is where i got confused. Whether the program is written according to that or am i getting wrong output.
According to the search results what I understood is, when I load the particular api url, I should get different ip address based on different machine connected with different network.
But am getting the same public ip (182.14.161.90) of the server where my project is deployed.
Can anyone pls clarify it and help me to fix the issue.
Any suggestions would be appreciated.
Thanks
It sounds to me like you have a Java Web Application deployed via tomcat and want to get a user's IP address.
The question you've linked in your question Finding public ip address using java is specifically for getting the IP address of the machine where the Java Code is running (for example, if you have a desktop application and want to get the IP of the machine that app is running on for some reason)
If you want to get the user's remote IP, it depends on your server configuration
If Tomcat is the ONLY webserver in your environment, and there is nothing in front of it, you can access the Request's remote ip using HttpServletRequest#getRomoteAddr, which will give you the IP address of the socket connection that initiated the Request.
This will work great unless you have a proxy server, like Apache HTTPD or Nginx in front of Tomcat, in which case you'll need to configure your server to send the
X-Forwarded-For header, and get the user's remote IP using HttpServletRequest#getHeader for example, request.getHeader("X-Forwarded-For")
If I've misunderstood your question, please clarify and let me know with a comment.
Im using TCP/IP sockets in java to try and create a client-server application. The program works fine when run locally and also over the local area network, but when I use the internet IP address the clients connection is refused.
I used this website to get my IP address and have added a firewall entry to unblock the port im using (port 4445).
I am almost certain the problem lies in some sort of security measure that is blocking the port. Does it matter that I'm running the client and server on the same PC but using the IP address from the previously mentioned website?
If I could get a list of ways to test the port is in fact open, or a list of things to try in order to get my program running, that would be great!
That website may very likely give you the IP address of the gateway through which your PC is connecting to the internet, and if the gateway is out of your control (which is most of the cases as far as I know) there's nothing you can do to use that IP address to test your program. Here's some advice:
Try http://aws.amazon.com, once registered you have one-year free access to a micro-server (which can be accessed publicly through DNS/Elastic IP.)
If your PC have a public IP address, you don't need that website to find out what it is. Just check your network adapter control panel.
Where is the server has been located? If your server is located in some commercial hosting, there is possibility that the ports you use are blocked. Also if you use modem with router or just router in your local network you should check nat table.
I'm currently writing an app that's to connect to a server over a wireless lan.
So far, I've got the IP address hardcoded into the app (which works perfectly), however, the next logical step is to be able to send the app the server IP address.
From what I understand, the router needs to broadcast the IP address over 255.255.255.255 - apart from that, I have no idea what to do.
Any and all help is greatly appreciated
edit
ok, so I know to get this working, all phones have to be on the same network as the server, which is fine.
What I need to do is get the phone to broadcast on the network whilst my server listens. From there, the server sends the app its IP address, then the rest of the code can continue.
Does anyone have a tutorial or anything I can follow to get both sides working?
one simple solution for you not to hardcode the server's IP or name (let us say it changes over time), would be for you to implement a name server on your network and have the android device call a local URL.
you could then post the current server's IP or name in the header of a web page on your local network. this response would then be used by android app.
I have a webpage behind a load balancer, and I want to display the user (for troubleshooting purposes) the IP of the actual node that the user is connected to (will be the same for a while due to sticky session)
I'm sure it's a very trivial question, but I want to be sure, what Java API should be used for that? will all APIs return me the request host? or will it be server dependent?
InetAddress.getLocalHost().getHostName() will give you the name of the server you are on.
InetAddress.getLocalHost().getHostAddress() will give the IP Address of the server you are on.