Few networking connectivity (windows firewall) questions with regards to virtualization

sram

[H]ard|Gawd
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Jul 30, 2007
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Hi to all,

I'm running Vmware pro and VirtualBox in my main machine at home. I'm building a small pentesting lab plus some other cool stuff you do with VMs and I came across few questions. Supposedly if you run a VM inside Vmware or VirtualBox with the setting of the network adapter set to bridge mode, then it will just be like a new physical machine connected to your router and it will get an ip address from the DHCP server running on the router. And if this is the case, each machine should be able to ping the other machine no problems. This is my understanding and this is how it has always been. However, sometimes it just doesn't happen. One machine will ping the other but not vice versa. I found one culprit though. It is the windows firewall. It seems like it blocks pings by default ( is that right?) and you will either have to turn it off or add a rule to allow ping requests. How come windows firewall blocks pings? I found that to be weird ! How is someone supposed to troubleshoot connectivity issues between dozens of machines? By the way, this is not always the case. Sometimes even if you turn off the firewall it wont still ping. I found that sometimes you need to mess with the virtual network editor settings in Vmware to fix issues. I also find this to be weird because default options in Vmware and Virtualbox should allow pinging both ways. One more thing, if windows firewall blocks pings by default, then why my main machine (the actual host) is pingable from all machines (either physical or VM) even though the firewall is turned on? I don't remember adding a rule to allow incoming ping requests!

Did you guys face similar issues? What's your comments?
 

sram

[H]ard|Gawd
Joined
Jul 30, 2007
Messages
1,340
Just to clarify, when I mentioned windows firewall I meant windows firewall present in the VMs I build which I can't ping after I install them. The other thing I want to add is that the VM in the virtualbox and the other VM in Vmware will both ping the default gateway or my router. The router will also ping them. However, the machines themselves won't ping each other which is mind puzzling for me. I was once able to fix this by going to Vmware virtual network editor and selecting the actual physical network adapter for the bridge mode or something similar.

Anyone with similar problems?
 

sram

[H]ard|Gawd
Joined
Jul 30, 2007
Messages
1,340
Anybody guys? Any virtualization gurus here?

- Machine A pings machine C and the opposite is also true
- Machine B pings machine C and the opposite is also true
- Machine A does not ping machine B and the opposite is also true

What gives? This is driving me crazy. It just doesn't make sense at all. The only abnormal thing in this setup is that machine A and machine B are in different hypervisor software, which shouldn't affect anything. Let's say machine C is the host machine.

If you have to ask why I have to use Vmware and Virtualbox: It is because one exploitable machine that I need to use only runs on virtualbox so I had to install and use it, although I normally use Vmware workstation. I'm a vmware guy.
 

Ready4Dis

[H]ard|Gawd
Joined
Nov 4, 2015
Messages
1,025
Hi to all,

I'm running Vmware pro and VirtualBox in my main machine at home. I'm building a small pentesting lab plus some other cool stuff you do with VMs and I came across few questions. Supposedly if you run a VM inside Vmware or VirtualBox with the setting of the network adapter set to bridge mode, then it will just be like a new physical machine connected to your router and it will get an ip address from the DHCP server running on the router. And if this is the case, each machine should be able to ping the other machine no problems. This is my understanding and this is how it has always been. However, sometimes it just doesn't happen. One machine will ping the other but not vice versa. I found one culprit though. It is the windows firewall. It seems like it blocks pings by default ( is that right?) and you will either have to turn it off or add a rule to allow ping requests. How come windows firewall blocks pings? I found that to be weird ! How is someone supposed to troubleshoot connectivity issues between dozens of machines? By the way, this is not always the case. Sometimes even if you turn off the firewall it wont still ping. I found that sometimes you need to mess with the virtual network editor settings in Vmware to fix issues. I also find this to be weird because default options in Vmware and Virtualbox should allow pinging both ways. One more thing, if windows firewall blocks pings by default, then why my main machine (the actual host) is pingable from all machines (either physical or VM) even though the firewall is turned on? I don't remember adding a rule to allow incoming ping requests!

Did you guys face similar issues? What's your comments?
I've run into (similar) odd issues as well, not even in VMs, on actual boxes. I did clean installs and then one box would have no issues with ping and file sharing, etc and a other one will not work. I'll be able to ping from but not to. I dont recall what I did but turning off the firewall seems to fix most problems as long as you're good having firewalls disabled (not a great solution typically). Lucky for me my ISP has me behind a double NAT so there is no way someone on the internet (myself included) can get into my network (would have to get through my router/firewall as well). This does leave my network wide open to anyone that's on it though.

PS. Sorry this wasn't a useful answer, more of an I feel your pain and wish you well.
 

sram

[H]ard|Gawd
Joined
Jul 30, 2007
Messages
1,340
I've run into (similar) odd issues as well, not even in VMs, on actual boxes. I did clean installs and then one box would have no issues with ping and file sharing, etc and a other one will not work. I'll be able to ping from but not to. I dont recall what I did but turning off the firewall seems to fix most problems as long as you're good having firewalls disabled (not a great solution typically). Lucky for me my ISP has me behind a double NAT so there is no way someone on the internet (myself included) can get into my network (would have to get through my router/firewall as well). This does leave my network wide open to anyone that's on it though.

PS. Sorry this wasn't a useful answer, more of an I feel your pain and wish you well.
Thanks for your comment. It makes me feel good. Well, in my case it is clear that it is something else in addition to the windows firewall because it even happens with linux machines. I haven't solved it yet. I think I'll just have to live with only one hypervisor running at a time and install all virtual machines that I want installed on it. I'll keep seeking a solution though.
 

Ready4Dis

[H]ard|Gawd
Joined
Nov 4, 2015
Messages
1,025
Thanks for your comment. It makes me feel good. Well, in my case it is clear that it is something else in addition to the windows firewall because it even happens with linux machines. I haven't solved it yet. I think I'll just have to live with only one hypervisor running at a time and install all virtual machines that I want installed on it. I'll keep seeking a solution though.
Well, good luck! Let us know if u ever figure anything out. I don't have many issues with my server, but it runs all Linux (host OS and docker containers) and stopped using VMs.
 

sram

[H]ard|Gawd
Joined
Jul 30, 2007
Messages
1,340
Just an update, I downloaded the remote desktop software TightVNC just to see if it can communicate between a virtualbox VM and a vmware VM. As I suspected, it didn't. It worked perfectly between VMs in the same hypervisor software OR between a VM and the host machine but not between a VM in virtualbox and another in vmware workstation. I'll see if I can get any help in vmware forums.
 
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