I have a laptop with Windows 10 2004 installed. I configureded Hyper-V and created two VMs: On one VM runs windows 10 to enclose serveral malware IM softwares which I have to use for working contacts. On the other VM runs ubuntu server 20.04 for development.
I configured Hyper-V with a virtual switch of type internal network and Hyper-V automatically specified the virtual switch with a static IP. I want to connect to ubuntu with machine name. So I specified ubuntu VM with a static IP and added an item in the hosts file of the host windows 10. Then I can use the remote over SSH feature of VS Code to develop node.js app in windows 10 host. Everything went ok till I had restarted my laptop.
After I have restarted the laptop, the IP address of the hyper-v virtual switch was changed. I couldn't reconnect to VM ubuntu any more because the VM ubuntu was configured with a static IP and default gateway based on the old IP of the virtual switch.
I checked the IPv4 properties of the virtual switch via UI, It's configured as "using the following IP", so I thought of the IP shouldn't change. But I was wrong. Each time after my laptop being restarted, the "static IP" of virtual switch always changes. This change breaks the connection to VM ubuntu.
So, is there any way to prevent the IP address of the virtual switch from being changed? Or some way to add name resolving mechanism to Hyper-V virtual switch (then I can configure using dynamic IP address in VMs)?
I just added an additional Internal switch via Hyper-V "Virtual Switch Manager" and gave it a name of "Static Switch". Then changed it's settings via Control Panel->Network and Internet->Network and Sharing Center->Change adapter settings. Right click on the new adapter and select Properties->Internet Protocol Version 4 (TCP/IPv4) and set a static IP that is not currently used on your network, for example IP address: 192.168.199.1 Subnet mask: 255.255.255.0. No other settings are required. Click Ok and close all the parent windows.
Add the new nic to the Hyper-V machine via the settings for the VM, Add Hardware->Network Adapter-Add. Select the 'Static Switch' and click OK.
Edit your client virtual machine network settings, in my case Ubuntu 20.10 so it's Wired Settings for eth1 (the new 'Wired Connection'). I disabled IPv6 and edited the IPv4 settings using a manual configuration (static IP) setting the IP address to 192.168.199.2 and a net mask of 255.255.255.0 and a gateway of 192.168.199.1 (The 'Static Switch'). No other settings are required. Click Apply and check that the network eth1 is connected.
You should be able to ping 192.168.199.1 from the client VM and ping 192.168.199.2 from the host machine.
This configuration will persist after a reboot and you can edit your hosts file on the host machine with whatever name you want, eg 192.168.199.2 my.vm.machine
Note: You will need to edit the hosts file as an administrator.
Don't use the default switch created by Hyper-V. As Miket25 said: "The default switch is made by HNS, and there may be settings that causes it to have a DHCP address on reboot".
Create a internal virtual switch using NAT annually. Here is the guide. And then connect VMs to this switch. The static IP address assigned to this switch will not be changed through rebooting.
Setting Static IP address in Ubuntu in Hyperv
Note: VM(s) are connected on "External Switch" in Hyperv
Check DNS IP address VM uses
gtan#master:~$ systemd-resolve --status
...
Link 2 (eth0)
Current Scopes: DNS
LLMNR setting: yes
MulticastDNS setting: no
DNSSEC setting: no
DNSSEC supported: no
DNS Servers: 192.168.141.81
DNS Domain: mshome.net
Check Gateway and Subnet Mask
gtan#master:/etc/netplan$ netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
default _gateway 0.0.0.0 UG 0 0 0 eth0
10.44.0.0 0.0.0.0 255.255.255.0 U 0 0 0 cni0
10.44.1.0 10.44.1.0 255.255.255.0 UG 0 0 0 flannel.1
10.44.2.0 10.44.2.0 255.255.255.0 UG 0 0 0 flannel.1
172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 br-894a4759cb12
172.18.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0
192.168.141.80 0.0.0.0 255.255.255.240 U 0 0 0 eth0
_gateway 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
eth0 Gateway = 192.168.141.81 mask 255.255.255.240 (192.168.141.80 is for broadcast)
Check eth0 IP address and subnet mask
gtan#master: ifconfig
...
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.141.85 netmask 255.255.255.240 broadcast 192.168.141.95
inet6 fe80::215:5dff:fe3a:1100 prefixlen 64 scopeid 0x20<link>
ether 00:15:5d:3a:11:00 txqueuelen 1000 (Ethernet)
RX packets 82792 bytes 103449317 (103.4 MB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 40353 bytes 10745111 (10.7 MB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
...
Edit "/etc/netplan/01-netcfg.yaml" to this (make a backup of the orginal 01-netcfg.yaml first: "sudo cp ./01-netcfg.yaml ./01-netcfg.yaml.bak"):
network:
version: 2
renderer: networkd
ethernets:
eth0:
dhcp4: no
addresses:
- 192.168.141.85/28
gateway4: 192.168.141.81
nameservers:
addresses: [8.8.8.8]
Shutdown the VM
In Hyperv, select the VM(s):
Go to Network Adaptor --> Advanced Features --> Set MAC address to "static"
All good to go!!!
After work, use "saved" instead of "paused" for the VMs'
Related
Two parts to this question:
1) Say a person is providing a wireless hotspot to me as I have no internet, when I access the internet what is my IP address set as?
--> Some companies basic level of fraud detection I assume is that the geographical location of the IP address is nowhere near the location of the IP of the device accessing whatever service it may be. So if you were on a mobile device accessing a site from a geographical location similar to the usual device, would this bypass this?
2) How can you find out the IP address of your device when on a hotspot
Say a person is providing a wireless hotspot to me as I have no
internet, when I access the internet what is my IP address set as?
When a person connects to a wireless hotspot, two IP addresses are set i.e. a Private IP address and a Public IP address. The wireless hotspot automatically allots the requesting device a Private IP address from a range of available IP addresses which is unique to that device. The device then connects to the internet via a Public IP address.
To break this down, when you turn on Mobile Hotspot, your phone's WiFi adapter turns on the router mode. Now the IP address is assigned by the wifi adapter running in router mode. In stock Android devices the default IP of your phone will become 192.168.42.1 and subnet mask of 255.255.255.0. However, this might change.
How can you find out the IP address of your device when on a hotspot?
In Windows, use ipconfig in cmd. Look for Default Gateway under your network adapter for your router's IP address. Look for IPv4 Address under the same adapter section to find your computer's IP address. Replace ipconfig with ifconfig in linux.
Use -ip neigh - in a linux terminal installed on android phone. It returns IP and MAC of devices connected to android hot spot.
I have succesfully built the CoAP protocol example for ARM mbed (https://developer.mbed.org/teams/sandbox/code/coap-example/file/0681e205d0e9/) on a K64F board. It comes out of the box, except for the server name (coap.me) changed to an internal IP address.
I see that it runs correctly and connects to the network:
[EasyConnect] Using Ethernet
[EasyConnect] Connected to Network successfully
[EasyConnect] IP address 192.168.1.15
[EasyConnect] MAC address 0e:43:54:d9:7c:71
Connected to the network. Opening a socket...
Calculated message length: 11 bytes
Starting server
Sent 11 bytes to coap://192.168.1.10:5683
I have set a computer that can connect to it. It can ping correctly to the board and I see that the ARP is negotiating with the correct MAC address.
I have launched an NMAP test and I see that the port is closed:
PORT STATE SERVICE
5683/udp closed unknown
If I set a CoAP client in the computer (Copper) I see no connection in the terminal.
What I am missing?
Moving this to the answer section as well, in case someone else runs into this problem.
If you want to use an mbed OS 5 device as a UDP server, make sure to call .bind() on the socket.
I have two virtual machines running on the same host and they are both in the same NAT Network. I started a fake bacnet device on one VM (say VM1) using the utility script volttron/scripts/scalability-testing/virtual-drivers/bacnet.py.
The device started up fine. Now from another VM (say VM2) on the same host and same NAT Network I ran the scan_bacnet.py but my fake device on VM1 is not getting listed.
I verified that the ip address on the BACpypes.ini file has the correct address of the host running the scan_bacnet.py script. I also changed the address in BACpypes.ini to include subnet mask (10.0.2.15/24) still no luck.
Below is the content of my BACpypes.ini on file on VM2
[BACpypes]
objectName: Betelgeuse
address: 10.0.2.15/24
objectIdentifier: 599
maxApduLengthAccepted: 1024
segmentationSupported: segmentedBoth
vendorIdentifier: 15
This is the command I ran in VM1 to start the fake bacnet device
python bacnet.py bacnet_registry.csv 10.0.2.5
I am able to ping from one VM to another and running a tcpdump on the source VM shows that the scan_bacnet.py is sending the whois request to the other VM. Running tcpdump on the destination VM shows that the machine is receiving the whois request yet the fake bacnet device isn't receiving the whois request.
What am I doing wrong?
You need to include the subnet mask in the virtual device command line:
python bacnet.py bacnet_registry.csv 10.0.2.5/24
Also you should check the firewall setting on both VMs. CentOS, for instance, defaults to blocking all incoming traffic. (You will still see it in the output tcpdump.) For BACnet you need to open udp port 47808 for all traffic (broadcast and direct).
I want to ping out of multiple ethernet ports. Is there an inherent restriction where u-boot only supports a single ethernet port?
Can u-boot support more than one ethernet port?
Yes, in recent versions of U-Boot (going back to at least 2012.10).
Salient code is eth_current_changed() and eth_set_current() in net/eth.c.
Is there an inherent restriction where u-boot only supports a single ethernet port?
No, recent versions of U-Boot can support more than one Ethernet port on the board.
When more than one Ethernet interface is available (as reported by the "Net" device list on startup, e.g. "Net: macb0, gmac0, usb_ether"), the environment variable ethact is used to define the selected Ethernet interface that is active.
Use the printenv ethact command to view the current selection.
Use the setenv ethact <port name> to change the active Ethernet port.
The U-Boot network commands, such as ping and tftpboot, will use the Ethernet port defined by the ethact variable. This preserves the command syntax with older versions of U-Boot, and the syntax is consistent regardless of the number of available ports (e.g. scripts do not change).
Each Ethernet port is assigned its own MAC address, using the following environment variables:
ethaddr: Ethernet MAC address for first/only ethernet interface (= eth0 in Linux).
This variable can be set only once (usually during manufacturing of the board). U-Boot refuses to delete or overwrite this variable once it has been set.
eth1addr: Ethernet MAC address for second ethernet interface (= eth1 in Linux).
eth2addr: Ethernet MAC address for third ethernet interface (= eth2 in Linux).
Obviously you can only (easily) access one port at a time.
There is also only one static IP address assignment, i.e. the ipaddr environment variable.
(I don't know what happens with an IP address acquired by DHCP using one port, and then the active port is changed.)
U-Boot> printenv ethact
ethact=macb0
U-Boot> setenv ethact gmac0
U-Boot> ping 192.168.1.1
gmac0: PHY present at 7
gmac0: Starting autonegotiation...
gmac0: Autonegotiation complete
gmac0: link up, 1000Mbps full-duplex (lpa: 0x2800)
Using gmac0 device
host 192.168.1.1 is alive
U-Boot>
Note that there also a rotation scheme that automatically changes the active port when the ports are down:
U-Boot> printenv ethact
ethact=gmac0
U-Boot> ping 192.168.1.1
gmac0: PHY present at 7
gmac0: Starting autonegotiation...
gmac0: Autonegotiation timed out (status=0x7949)
gmac0: link down (status: 0x7949)
ERROR: Need valid 'usbnet_devaddr' to be set
at drivers/usb/gadget/ether.c:2362/usb_eth_init()
macb0: PHY present at 0
macb0:0 is connected to macb0. Reconnecting to macb0
macb0: Starting autonegotiation...
macb0: Autonegotiation timed out (status=0x7849)
macb0: link up, 100Mbps full-duplex (lpa: 0x41e1)
Using macb0 device
ping failed; host 192.168.1.1 is not alive
U-Boot> printenv ethact
ethact=macb0
U-Boot>
I am binding to a multicast group and port to listen a multicast stream. Since adding the group membership (via IP_ADD_MEMBERSHIP) requires specifying a specific network interface, what will happen when that interface IP address changes?
Do I have start again with a new socket and add membership? This is related to Linux/C environment. I do see some packets comming in without changing IP, but I feel I have to restart.
thanks,
gl
The Linux kernel appears to be tracking the interface based on the interface identifier rather than the interface IP address. From a couple of experiments, it looks like your application won't need to have any special handling
Experiment 1: Host Receiving
Here's an experiment I put together with Ubuntu to test if the host will continue to receive across the interface IP change.
$ uname -a
$ Linux joel-VirtualBox 3.16.0-34-generic #47-Ubuntu SMP Fri Apr 10 18:02:58 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
I have a simple Python test script for running a multicast receiver on a network interface eth2, identified by static IP 192.168.33.11:
import socket
import struct
sock = socket.socket( socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP )
sock.bind( ('',50400) )
sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, socket.inet_aton('239.254.2.4') + socket.inet_aton('192.168.33.11') )
while True:
print sock.recv( 2048 )
sock.close( sock )
Once running the python script, I can verify the membership by running:
$ netstat -gn
lo 1 224.0.0.1
eth0 1 224.0.0.251
eth0 1 224.0.0.1
eth1 1 224.0.0.1
eth2 1 224.0.0.251
eth2 1 239.254.2.4
eth2 1 224.0.0.1
From another PC, I ran a multicast sender, sending to 239.254.2.4:50400 and verified the data is printed. I then changed the static IP to 192.168.33.12 and verified the membership is still reported by netstat and my python script can continue to receive data.
Experiment 2: IGMP Membership Reports
I put another experiment together to see what happens to the IGMP membership reports:
As you can see when the change of IP address happens, no new IGMP report for 239.254.2.4 is generated. But when the script is killed, an IGMP Leave message is sent.
This could be considered "a hole" though any switch or router that is performing IGMP snooping or multicast routing will be periodically issuing IGMP queries. Our host will respond to this query by sending its current memberships (including the membership for 239.254.2.4).
I don't think you have to rejoin the group. Both the localhost and the router only have a count of members, and in both cases if it's non-zero it will deliver the multicast internally. But I could be wrong.