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fneto
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Stuck ARP entries with Virtual Machines

Tue Oct 02, 2018 12:51 am

Hello All!

I'm passing through an strange problem and I'd like to ask for your help!!

My scenarios is the following:

I've a ESXi host with some virtual machines, this machines are connected in a dell switch and the dell is connected in a RB1009.

My problem is that the VM are working normally, all go them are using fixed IP address, but when I need to reboot any of them (by example an windows server after a windows update), the server start without network and companies about duplicate ip address.

I've checked everything and I don't have any conflict, neither any DHCP server in this network segment.
What I've noticed is that the ARP table in the RB shows the correct information (mac address and IP address) with only the enabled information in the botou, but the complete option is greyed.

If I force the deletion of the ARP sometimes 20 times, or if I disconnect the VM machine from the network for about 5 minutes and reconnect it again without do anything the server start to work normally again.

I really don't know what to try anymore, some times I disabled the network or change the VM mac address and it works, sometimes it didn't work too, and it was running fine from more than 2 years, only now in after some recent router OS upgrade it starts to appear, but I can't say what upgrade cause this!

Does anybody have seem some problem like this?
 
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Anumrak
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Re: Stuck ARP entries with Virtual Machines

Tue Oct 02, 2018 5:14 pm

Does it happens without connection to RB?
 
fneto
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Re: Stuck ARP entries with Virtual Machines

Wed Oct 03, 2018 12:39 am

Hi Anumrak!

I don't know if I understand correctly your question but all the hosts ara connected trough the Dell Switch.

I will swap this switch for a new one with 10Gb ports, but when it happens the arp table on the switch are always ok!

Thanks!
 
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Anumrak
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Re: Stuck ARP entries with Virtual Machines

Wed Oct 03, 2018 2:15 pm

Hi Anumrak!

I don't know if I understand correctly your question but all the hosts ara connected trough the Dell Switch.

I will swap this switch for a new one with 10Gb ports, but when it happens the arp table on the switch are always ok!

Thanks!
Cool :)
 
fneto
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Re: Stuck ARP entries with Virtual Machines

Wed Oct 03, 2018 5:58 pm

An update about this issue.

I have another ESX host that are connected trough a VLAN from another site to this RB in a FO link.

This link enters in a huawei switch and goes directly to the RB1009.

Today I've installed a new VM with linux, the installation goes normally and in the first boot everything was ok. Then I've installed the vm-tools and reboot the VM and the problem starts to appear as you can see in the image attached.

Now the error display an information of a mac address using the same IP address, but this mac address didn't exist in my network. I've checked everything, it appears to be a cisco device (we don't have any cisco in the network topology) and as you can see, after some trial restarting the network the device get the ip address and is working fine!
Captura de Tela 2018-10-03 às 11.27.02.png
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fneto
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Re: Stuck ARP entries with Virtual Machines

Thu Oct 04, 2018 2:48 am

I think we have found the problem, the Huawei switch have a loop with a router and a BGP link, we split these networks in two different VLANs and the problem was solved!

Thanks!

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