I was trying to do TCP connection in smart watch
but I can't ping my watch from laptop using same network and error- connection refused when tcp connection reference from (https://www.tutorialspoint.com/sending-and-receiving-data-with-sockets-in-android).
what can I do for currently and asking for solution
smart watch model -DA08.
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If you are currently paired with the watch, then the default network is probably bridged over BT.
You could test, while BT is disabled.
Or specifically request wifi network, see https://developer.android.com/training/wearables/data/network-access#requesting-wifi-connectivity
Related
I created two Qt apps: one client and one server.
I use them to send some data for handle a remote device.
If I am in localhost I haven't issues about them, but when i search to connect them by internet i don't know how to find correct Ip server to connect Socket Client.
How i can find this ip node?
Is there a class to find It?
you cannot find it automatically, if this is what you're asking about.
In real life you would deploy your server on some publicly accessible host, give it a domain name (important part as your host can change the IP address at any time) and connect the client via the DNS domain.
However if you're just playing around and you want to show to the world that your app works, specifying the IP address of the server in your client code would be perfectly fine (assuming you're running both the server and the client in the same network).
In that case, if you're running mac/linux run the command ifconfig (or just ip depending on the distribution). On Windows you can run the command ipconfig. Both windows and linux will give you a similar output resembling this:
Pay attention to the network adapters. There can potentially be many of them. You may have some emulated adapters if you have docker or VMWare, you may have the wireless adapters if you have a WiFi card, and then the ethernet adapters if your computer can connect to the the internet with an ethernet cable. Each of these adapters specifies a different IPv4 address. You want to pick the one that is connected to the same network as your client. So for instance if both your server machine and your client running machine are connected to the same wifi, you pick the address from the Wireless LAN adapter
What we have
My office network have a new 20mbps dial-up connection. The internet is connected to DLINK 600-L Wifi Router. An LAN port of router is connected to DLINK's gigabyte switch that connects all the PCs in the building. We do have a good traffic in internal network due to the office software activities. Before this new internet connection, we used static IP routing in another router. But now it is using DHCP.
My problem
When we connect to wifi and browse, we are getting only 1mbps to 2mbps instead of 20mbps. Also often the download is broken and fails in middle.
Test I have tried
Opened 2 terminals.
Started a ping to router in terminal 1.
ping 192.168.0.1
Started a download in terminal 2.
wget http://www.dlink.com/-/media/Consumer_Products/DIR/DIR%20600L/Manual/dir600L_manual_100.pdf
Result: The ping was 5ms - 10ms when started. But as the download started at 512kbps - 2mbps, the ping started to rise up to 10000ms and the download speed went down gradually to zero. Thus download failed.
You're suffering from Bufferbloat. In short, some router uses too much buffering under load, which causes extremely high latencies.
The solution would be to replace the DLINK with a debloated router (I recommend a recent version of OpenWRT with fq_codel), and set up traffic shaping to ensure that the congestion happens on that particular router.
I have a puzzle I am not able to figure out, I would appreciate any help.
I am connected to a remote desktop using windows default remote desktop utility (Windows 8 locally, Windows 7 remotely).
The remote desktop is not in the same sub-network as my own.
Connection is made through default port 3389. Using Wireshark locally I can confirm the TCP connection being established and the data flow.
Running Wireshark in the remote desktop, I don`t see any flow of data between the two computers.
If I send a ICMP ping from the remote desktop to my computer, it works well and I can see it in Wireshark both remotely as well as locally. But if I send the ICMP ping from my computer to the remote desktop, it fails. I see it leaving my computer through Wireshark, but it never reaches the remote desktop (I don`t see it in Wireshark).
I don't think it is a firewall issue (specially since it can't explain why Wireshark won`t capture the port 3389 RPC flow).
Does anyone have any idea of what might be going on?
I found the main issue.
In Wireshark, turns out it is possible to configure the capture interface with a filter.
To change it, go to: Capture->Interfaces
On the interface being used, stop capturing to enable the Options, there it is possible to configure a capture filter.
When some network connection isn't working right, one thing in my bag of tricks is to try opening a telnet connection to it. I don't expect to be able to do anything useful with this connection, but knowing if I can or can't connect is helpful in diagnosing the problem.
So today we had a problem where our app server couldn't open the JDBC connection to our database. However, it works fine when the app server is on the same physical box as the database. Aha, I thought, there must be a firewall blocking that port. So I tried to telnet to that port, and couldn't connect. As a control though, I also telnetted to a database on a box we could connect to and that failed as well. So, the situation is, somehow whatever is listening on that port accepts a JDBC connection from JBoss, but rejects a connect from telnet. How does it distinguish these two connections? Different protocol? Password embedded in the connection request?
Sounds like the database is only accepting connections on the local interface. Is your app server configured to connect to the database via its IP or via either localhost or 127.0.0.1?
I am trying to send data using the AsyncUDPSocket class. And I can send data using the iPhone simulator over the wire to another machine that is running a simple C-coded listening server. I can also receive data over the wire using a client connected to the simulator(server). However, when I tried the same over Wifi, using the simulator, I could only send data but not receive any data.
I read on another post, that unicast data makes this possible. How can I acheive this using AsyncUDPSocket?
Thanks,
Angelo.
Ok, I figured this out. A newbie kind of thing, really.
When I set my Mac network preferences to Ethernet, I get an IP for me to communicate. However, when I turn Airport(Wi-Fi for more newbies) ON, and ethernet cable disconnected, I checked my network preferences, and sure enough my IP address was a different one.
Spoke to a friend (an ace in networking) and the thing clicked immediately: On WiFi networks a DHCP server allocates an IP address. This IP address has to be reserved, at the very least, at the DHCP server. Since my IP was not reserved, I had to change the IP address, in my udp_client.c file, recompile and run the client to connect.
BTW, I can now communicate between my iPhone and my PC using my local WiFi (office) network.
For any who might face the same problem, do not be assured that the IP address of your mchine is the same, when you switch from LAN to Wifi, and use the device mostly for WiFi reated testing. :)