I am trying to establish LAN connection between my two laptops using Ubuntu on both. But it shows auto is connected on one laptop but other remains disconnected.
Is there any a hardware issue or a software issue? Am I forgetting something else?
Are you directly connecting them, or using a switch in between? If you're directly connecting them you need a crossover cable and not a straight. Also make sure they're both in the correct subnet.
https://learningnetwork.cisco.com/thread/13249
Also check out the following link; http://en.kioskea.net/forum/affich-25120-how-to-connect-two-laptops-using-lan-cable
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On a local network I'm sending a WOL (Wake-On-LAN) packet using sendto to the target MAC address. The code for that works without any problems and the target machine is turned on correctly. The problem is, that I don't know if the target machine has a LAN cable attached or not. If it's not attached, then the whole process fails. Unfortunately, sendto is unidirectional, so I don't know if my magic packet arrived.
I'm wondering about the best and fastest way to find out if WOL succeeded or not. Waiting for the device to boot up completely so I find out get and ping its IP address takes way too long.
Is there a way to "ping" a MAC address, i.e. get some sort of Layer-2-reply?
I need this solution for a Delphi application, but if you have a solution for a different language at hand you're welcome to post that as well. Thank you!
I have a Raspberry Pi with a hat to control my sunscreens. Works very well when I use the normal internet connection.
I have added code to detect when I'm on the local network and even using mDNS / Bonjour I detect the Raspberry Pi from iOS and get it's local IP address. But then if I do a request to the Pi using the local IP address I get a (kCFStreamErrorDomainSSL, -9824) error. The cause is obvious: the SSL certificate on the Pi has the FQDN in it and of course that is not the same as 192.168.2.13 or whatever.
But then the big question: how to solve this.
One idea could be to make sure from outside the router resolves to my FQDN, from the inside I should make sure that the FQDN resolves to the local address my Pi is on. But the only way I could imagine how I pull that off is making the Pi a DNS and DHCP server. Although I could do that of course I am starting to think that I make it way too difficult and there should be other solutions.
One maybe easier option might be to bring another server process in the air on the pi and if I detect the Pi using bonjour not go through the http(s) route but use the alternative solution (sockets?)? Any suggestions appreciated.
I have a headless raspberry pi with a wifi dongle and I want to use wifi two ways.
1) To make the rPI a wireless access point when there is no local wifi access point so I can connect to the rPI from my iPhone.
2) When wifi is available use the wifi dongle to do normal connection to the internet.
I think I know how to do each of these individually. It wasn't easy but I now have it connecting to my local wifi at home.
I see references to using hostapd and dnsmasq with wifi to make a local access point but they mostly assume internet connection comes from ethernet.
I'll be studying these in more detail. However I don't even know if the end goal of using the same configuration to fill both needs with one wifi dongle is even possible.
Obviously I can create two sets of config files and a script to swap them as needed but that only works if I have a connection already so I can log in.
If I add a jumper or switch to the rPI GPIO interface I could run the configuration script at startup and let it read the switch.
I might try to make the script look for an existing wifi link and go to access point mode if it doesn't find one it can access.
This would probably be a steep learning curve for me but I could probably figure it out eventually.
What I am trying to figure out now is whether I can avoid these potentially complex solutions by creating a single configuration that does both. Is a single wifi dongle sharable between these functions?
Note: I don't need it to do both at the same time. I just need the decision to be automated so it happens automatically during boot.
It is possible, although tricky to get right. (For example, what happens if you boot up, don't see an existing network for a second due to interference, then wrongly create your own network?)
Take a look at the "iwlist" command. It can scan and tell you what SSIDs (base stations) it sees. Then you can use 'grep' to see if your home network is on the list, and use that as your decision.
How the communication between two pc will be done and how the communication in the network will be done ? How do they bot coneect to the internet??
I m assuming may be one pc has spoofed another pc address.
It depends how the machines' MAC address appear onto mac routing table.
https://superuser.com/questions/17696/what-happens-when-two-pcs-have-the-same-mac-adress
Exactly. What eRIZ said.
Sometimes the machines will refuse to connect due collision OR one computer will connect before the another bouncing the other one of the network.
But yeah, it depends how they are configured.
On our team we have a standardized development setup where we have a Win8 workstation with various VMs running on Hyper-V. All development takes place on a VM.
I was having an issue where I couldn't check out a project from a Team Foundation Server using VS2012, it would start checking out, but then the connection drops. I fired up Wireshark to check what's happening, but then it worked fine. I double checked:
When Wireshark(or rather WinPcap which is doing the actual capture), running on the workstation, is capturing packets from the VM's virtual NIC, everything works fine.
As soon as I stop the capture, TFS can't check out.
So I can't even properly inspect the network traffic to diagnose the issue, because the act of inspecting traffic changes it. Heisenberg would be proud!
I thought it might be an issue with Wireshark overriding some check-sum offloading settings, but it seems not to be the case.
So what else can be affected by running Wireshark? I rather thought that the point of packet sniffers is that they don't change the packets as they capture them.
That means you are picking traffic that normally would not be picked by the vmnic.
Try to check on mac address level what is happening. Maybe mac address conflict between VMs ?
ps. You can whireshark without promiscuous mode. The the Heisenberg rule should not apply :)