Connection timed out error - networking

Am trying to connect a device to my PC via ethernet. while attempting to connect its showing "connection timed out". why do this happen...i need to rule out this problem to carry forward my project.
am trying to connect via ethernet.
please help

Do you mean trying to connect using Point To Point Protocol over Ethernet (PPPoE)? Did you assign the IP addresses for both ends? In order to connect two devices, both sides have to speak the same language (protocol) and should be configured properly.

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SIM5320A, device connected to 3G Network but can't ping server

I've been trying to make this SIM5320A module send HTTP requests to my server but even though it appears connected to the internet I can't seem to ping any server or make any requests.
I'm sending AT commands through a terminal on my Linux PC.
AT+CPIN appears READY
I've configured through the AT+CGDCONT, AT+SOCKSETPN = 1 and AT+CGSOCKCONT commands, adding my service provider's APN.
AT+NETOPEN returns OK. Running it again returns Network is already opened.
AT+CPSI? show's that it's connected to the WCDMA network and is online.
AT+IPADDR throws a proper IPv4 address.
So I'm trying to do AT+CPING="google.com",1 but it just won't connect.
I've even been able of sending a SMS and reading GPS coordinates, just failing in the internet stuff.
Am I missing any configuration steps? There is so little information online on this device.

ESP8266 DNS Lookup with Hostname ending in ".local"

Three or more years ago, I made an Arduino project for a NodeMCU (ESP8266) that connected to my MQTT server. I needed to make some changes to the code (unrelated), rebuilt, and was unable to connect to my MQTT server!
After doing some research/debugging, I found that the issue is that the latest board library (2.7.4) is apparently only doing mDNS lookups and not falling back to [or just using] DNS like it used to! It's not failing either - its returning other, random IP addresses (usually a random computer on the same subnet) so I can't trap for the issue. As a result, when I try to connect to my host "mqtt.local", it is unable to get the correct IP address and fails to connect.
I've been able to work around the issue by adding another DNS entry for just "mqtt" (dropped ".local") and connect that way but it is less then ideal. Is there any way to disable mDNS or manually do a DNS lookup for a .local address? (tried setting LWIP_DNS_SUPPORT_MDNS_QUERIES to 0 but that didn't help)
For what its worth, I do have a mDNS proxy running (since Apple has the same issue with .local hostnames). I can get the correct IP on my Mac using the mDNS proxy so even with mDNS, I should be able to resolve the address!

Using WAN IP to connect to a device connected to router

I have a router (belkin) with many devices connected.
I ran a application on one my devices and the application assigned a port number for remote connection.
Now for me access this device i tried doing something like:
wanipaddress:port
But unable to connect. I am not sure if the router can be used to accomplish the above.
Any suggestions on how to achieve the above?
P.S my router assigned unique LAN IP to all the devices.
I achieved the following using Port Forwarding mechanism. A port forward is a way of making a computer on your home or business network accessible to computers on the internet, even though they are behind a router.
I found the following tutorial to be useful:

Wireless with 802.1x

I have the following problem.
I'm trying to configure my router (Iskratel F50 or Mikrotik hAP lite) to control WiFi traffic with 802.1x and some kind of RADIUS server. But, when I configure everything on the router, and try to connect on that WiFi with my Android phone, it just refreshes the list of available wifi connections and shows the test connection as "saved". Nothing else happens.
If I'm right, the router should send UDP package, with access request data to RADIUS server or whatever it is on specified IP, right?
Can someone help me?
I need my device to get access request and then decide to allow or deny access to that client, depending on other details.
At the RADIUS IP is an Arduino device, that shows all data that came on RADIUS port to the LCD.
Thank you.
Generally, for a 802.1x-authentication over RADIUS, one would indeed expect to see several packets. The default ports for RADIUS are 1812/UDP (authentication) and 1813/UDP (accounting).
The first packet your router sends to the RADIUS IP should already have a User-Name-attribute. The connecting device should query the user for this. So, when you connected to that SSID, did your phone prompt you for a username (and password)?

IOS4 - Send data using UDP socket on Wifi

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. :)

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