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miechovy
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Multiple VMs - network issue

I'm using Vmware Workstation Pro since few years, since v. 14 has been available. Till today I notice same problem (v. 16).

Namely when I run multiple VMs (for example 10 or 12) at the same time, I have a problem with network connections. A command PING has a response, but PING to domain is not resolving. Next, if I close most of VMs, the network is working properly.

It turns VMware has a network problem with multiple VMs runs at the same time. I know - maybe VMware Pro is not dedicated for such of environment, but we have to use Workstation Pro to our project.

My question is, how can I debug or where to search information about this issue? Is it a problem with VMware DNS or something? (my network in VMs are configured as a NAT).

>ping google.com
Ping request could not find host google.com. Please check the name and try again.

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miechovy
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Hello.

One more time I have to refresh this topic.

Interesting, but the right solution to solve this problem is following: https://communities.vmware.com/t5/VMware-Workstation-Pro/VMWare-Workstation-Pro-15-NAT-drops-after-a...

Seems there is a unknown problem with subnet 192.168.43.0 and gateway 192.168.43.1

After changed to X.X.100.0 and X.X.100.2 for vmnet8 (NAT) my problem is solved for now.

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wila
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Hi,

Is this in the guest or host?

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Wil

| Author of Vimalin. The virtual machine Backup app for VMware Fusion, VMware Workstation and Player |
| More info at vimalin.com | Twitter @wilva
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miechovy
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The problem is in the quests. My host is installed on Linux and has a good hardware performance.

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wila
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Hi,

I thought you would say that, just wanted to make sure.

Yes, you are correct that it is likely to be a DNS issue.

Next thing to try is what the result is of this:

nslookup google.com

Note: run in the guest of course (I should also be explicit)

--
Wil

| Author of Vimalin. The virtual machine Backup app for VMware Fusion, VMware Workstation and Player |
| More info at vimalin.com | Twitter @wilva
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miechovy
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>nslookup google.com


DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: my_ip_address_cutted

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to UnKnown timed-out

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wila
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Hi,

So yes, it is a DNS issue.

You mentioned you used a NAT connection on a Linux host.

But you also said "if I close most VM's then it works normal"... that one is weird.

Are (some of) your VM's using a fixed IP address perhaps?

--
Wil

| Author of Vimalin. The virtual machine Backup app for VMware Fusion, VMware Workstation and Player |
| More info at vimalin.com | Twitter @wilva
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miechovy
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Hi.

IP addresses are assigned automatically, but a DNS IP direct to local address to the host (my DNS server).

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a_p_
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Some thoughts:

  • What operating systems do you run in the guests/VMs?
  • Have the guests been cloned, or manually created?
  • Can you confirm that all guests have different MAC addresses, and - in case of Linux - different machine-ids?
  • Does the name resolution work with querying the DNS server directty, e.g. nslookup www.vmware.com <DNS-Server-IP>, or dig www.vmware.com @<DNS-Server-IP>?

André

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miechovy
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Hello Andre.

  • What operating systems do you run in the guests/VMs?

Windows 10.

 

  • Have the guests been cloned, or manually created?

Full cloned and works as an independent instances.

 

  • Can you confirm that all guests have different MAC addresses, and - in case of Linux - different machine-ids?

Yes - the MAC addresses has been randomly generated after cloned.

 

  • Does the name resolution work with querying the DNS server directty, e.g. nslookup www.vmware.com <DNS-Server-IP>, or dig www.vmware.com @<DNS-Server-IP>?

No, we use a localhost DNS (configured to 8.8.8.8 for resolving domain names) - unavailable from external network.

 

What do you mean - different machine-ids?

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a_p_
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The reason why I mentioned "machine-id" is related to DHCP with current Ubuntu version (see e.g. https://kb.vmware.com/s/article/82229).
What you may try to further troubleshoot the issue is to run s.th. like portqry to check whether the DNS server's port 53 (tcp/udp) can be reached.

André

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miechovy
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I'm not trying to say you are right or not, however I mentioned this issue has a place when I run dozen VMs, not a few. I think it is a problem with performance some thing. But I do not know how to determine, it concerns VM problem or my custom DNS server problem on Linux platform.

I just checked and all VMs has a different IP addresses.

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a_p_
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Please don't get me wrong, it's not about being rigth or wrong. I'm just trying to rule out possible issues.
What I'm actually thinking of at this point, is that VMware Workstation might have an issue with UDP traffic - I understood, that e.g. ICMP (ping) is still working in affected VMs - in your case (many powerd on VMs), but I'm currently not sure how to figure this out.

André

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miechovy
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The communication between VMs is correctly, I suppose. Command of PING from quests to host and host to quest and quest to quest is working properly. As you know right now the problem is when multiple VMs is running. Ping command probably is not a problem, rather communications to local DNS and back. For example in first post I write that PING is correct, but domain name is not resolved from command line or browser.

I noticed that something is "stuck" - sometimes DNS works, but mostly machines cannot get access to internet.

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a_p_
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Can you please try the following on a VM that cannot resolve names?

Start nslookup in interactive mode, and configure it to use a virtual circuit for requests. After that enter an URL to see whether it gets resolved.
With vc enabled, DNS queries are supposed to use TCP rather than UDP.

Sample:
nslookup
> set vc
> www.vmware.com 

André

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miechovy
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Hello Andre.

Sorry for huge answering delay. However it is just doing your last instruction and the result:

 

C:\Users\test>nslookup
Default Server: UnKnown
Address: my_external_IP_server

> set vc
> www.vmware.com
Server: UnKnown
Address: my_external_IP_server

*** UnKnown can't find www.vmware.com: Unspecified error
>

 

 

And another checking:

 

nslookup google.com
Server:  UnKnown
Address:  X.X.X.226

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** No internal type for both IPv4 and IPv6 Addresses (A+AAAA) records available for google.com

 

 

Please, let me remind weh use NodeJS DNS server on the host (Debian 11): https://nodejs.org/api/dns.html

 

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miechovy
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@a_p_I think there was a similar problem on the VM Fusion: https://communities.vmware.com/t5/VMware-Fusion-Discussions/DNS-resolution-via-NAT-breaks-intermitte...

I have this problem as well in a VM running Ubuntu 7.04, except that in my case the problem starts after about a day of using the VM. 

 

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miechovy
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The issue can be recreate at following instruction:

1. Create at least 2 to 10 VMs and let them works by whole day or two.

2. After several/dozen hours on the VMs you can observe very slowing DNS responses eg. nslookup google.com (dns not responding)

3. If you restart the host machine or VMware services, then the DNS-NAT interface will be very quickly with responses as at beginning in a first day.

I think we have a VMware bug in NAT/DNS/interface.

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a_p_
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That's interesting. Maybe @Mikero has some insight?

André

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miechovy
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Please let me remind, we use Debian 11 on host machine. I do not have a possibility to reproduce the problem on Windows host, but the previous links I have posted tell us about macOS/Vmware Fusion as well as Linux. 

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miechovy
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Hello.

One more time I have to refresh this topic.

Interesting, but the right solution to solve this problem is following: https://communities.vmware.com/t5/VMware-Workstation-Pro/VMWare-Workstation-Pro-15-NAT-drops-after-a...

Seems there is a unknown problem with subnet 192.168.43.0 and gateway 192.168.43.1

After changed to X.X.100.0 and X.X.100.2 for vmnet8 (NAT) my problem is solved for now.

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