I'm working with KVM/VirtualBox and OVS. I have two bridges on a host machine, br0 and br1. A VM is connected to br0. The VM is able to ping br0 but it is also able to ping br1, to which it is not connected. Also, I made an iperf server on the VM and a client on the host machine and when I gave the ip of br0 a connection was made and data was transferred but when I gave the ip of br1 a connection was made but no data was able to transfer. All ips are contained in the same subnet. Can someone explain what is happening?
I can explain on "why br1 address is pingable". This is because in linux when packet is treated as "local-delivery" packet it is received in common point, where source interface is not important. So packet to ANY local interface may be received from any network interface.
Related
I have a Soft PLC running inside a VMWare environment (Guest - Windows 8).
I want to connect to it from the Host (Windows 10) using the internal connections without having to set up a physical network switch.
My understanding of the documentation states that this should be achieved by Host only networking
https://docs.vmware.com/en/VMware-Workstation-Player-for-Windows/15.0/com.vmware.player.win.using.doc/GUID-93BDF7F1-D2E4-42CE-80EA-4E305337D2FC.html
And I've my PC Set up as:
The Network card in the Guest is set up as 192.168.0.244
On the Host, the network VMNet1 (Should be the DHCP Server) is Dynamic (DHCP) and resolved to 192.168.67.1 and VMNet8 (Should be the connection to the Guest) is also DHCP and has resolved to 192.169.73.1
All subnet masks are at 255.255.255.0 (DHCP defined?)
Even if I assign VMNet8 or VMNet1 to physical IP at 192.169.0.1 or 192.169.0.244 or 192.169.0.1 or even 192.168.0.12, I cannot ping the network card inside the host.
Am I missing something here with my setup? What am i doing wrong or has anyone got a step by step process for setting up a direct network connection between the Guest and host for testing communications without an external switch?
(I've disabled teh network connections between each setting change)
Found the issue.
The VM should have been set to NAT
The Network address of the adapter Inside the Guest set to the IP address I'm looking for
On my Host - VMNet 1 left alone as this is the DHCP Server
And set the VMNet 8 (Bridged connection between Guest and Host) to an IP address within a range of the subnet
And after disabling and re-enabling the connections, I can ping the PLC (192.168.0.1) running in simulation on the Guest from outside in the Host.
(Allows me to test node-red on the host connecting via OPC to PLCSim Advanced running on the Guest).
Hello Everyone!
I want to know that is there any way to access a photocopier machine which is connected to a computer through Ethernet wire and that computer is connected to my WiFi network?
P.S: What if I don't know the IP assigned to that Photocopier machine?
If the wireless network is part of the wired network you should have any problem reaching the photocopier.
If you don't know the IP address, you can reach it by host name if the DHCP and DNS are working properly. If you are on an Active Directory infrastructure and DHCP and DNS are integrated it should be transparent.
If you are on your home with a "home" router they usually do the hostname to IP resolve (DNS).
You can nslookup hostname in your machine to see if your dns is resolving the ip address. you can also ping hostname or ping ip address to test that you can reach the desired host. Some hosts block ping (ICMP) requests, please note that ping is ping does not respond is not a definitive solution.
Please note that in your home router you should use your router or default gateway to be the DNS also, and then add the google public DNS or your ISP.
Also when connecting the access point to an existing network you may have 2 DHCP servers providing IP addresses to hosts, you should disable DHCP on the Access Point and connect the AP to the network using the switch port and not the WAN port (the WAN port will try to do NAT and assign a different set of IP addresses).
Running a Centos 5.11 machine with two network cards.
One is facing the internal network (private IP), the other the Internet (public IP).
Because we had some issues lately with it (ARP collision - but that's not the point here!), I started verifying its config. And I find out the broadcast set for the public IP is wrong.
IP is xxx.xxx.xxx.25
Subnet is 255.255.255.240
So basically we should have:
Network xxx.xxx.xxx.16
First IP xxx.xxx.xxx.17
Last IP xxx.xxx.xxx.30
Broadcast xxx.xxx.xxx.31
But the broadcast is automatically set to last host xxx.xxx.xxx.30
If I change it using command line, it is reseted back to the same IP once I do a service network restart...
I had to edit /etc/sysconfig/network-scripts/ifcfg-eth0 for the broadcast to stick to what I wanted.
My environment has 2 hosts and a VM on each host. NVGRE tunnel is created, as VMs and Hosts belongs to different subnets. I am using Windows server 2012 R2 hosts and same VMs. Hosts are connected back to back. If I put VMs and Hosts in same subnet Ping works.
Both the VMs are receiving ARP requests and responses from each other. ARP cache of each VM is having dynamic entry of other VM.
BUT ICMP request packet from VM is not even seen on its Host.
You cannnot just ping from one host to another host.
To ping provider address from your host, -p option is needed.
Example:
$address = (Get-NetVirtualizationProviderAddress).ProviderAddress
ping -p $address
Please put virtualization lookup records when you need more help.
Run following commands as administrator.
Get-NetVirtualizationLookupRecord
Get-NetVirtualizationCustomerRoute
Also make sure your VM's firewall allows ICMP echo.
I have created two network in openstack (Hawana -ubuntu 12.04 LTS) (192.168.1.0/28, 192.168.1.16/28) and both network have their instances. Instances can ping the gateway of another network
but instance can not ping another instance in that network.
for example Network one: 192.168.1.0/28 gateway is 192.168.1.1 and Instance ip 192.168.1.2
network two: 192.168.1.16/28 gateway is 192.168.1.17 and instance ip is 192.168.1.18
now 192.168.1.18 machine can ping 192.168.1.1 but not 192.168.1.2
please tell me the exact problem of it.
The two networks (subnets, actually) should be connected via a single router for instances on the networks to reach each other.
And as #Brenne mentioned, ICMP packets (ping) have to be explicitly enabled in the security group. By default, they are not allowed.