EVE-NG on VMware ESX Strange ARP Problems?

KB ID 0001601


I use EVE-NG a lot, it’s an awesome tool. Also I’m lucky enough to have my own ESX servers, so that’s where it lives. I’ve noticed this problem before, but I’ve either given up, and done something else, or it’s manifested itself in an ‘odd’ way that I can work around.

If you’re new to connecting EVE-NG to a live network you might want to read the following post first;

EVE-NG (VMware) Connecting to the Internet

When setting up a new lab, I connected a Ciso IOL router to my cloud object, and it successfully got an IP from DHCP, but could not communicate with the outside world. So I replaced it with a Cisco (Dynamips) router, same thing! So I replaced with with a Cisco ASAv, same thing!

EVE-NG Not connecting to Network

I moved the EVE-NG machine onto its own standard vSwitch, (no difference).

EVE-NG Not connecting vSwitch

I hadn’t committed the ‘schoolboy error‘ of forgetting to allow promiscuous mode on the port group.

EVE-NG Promiscuous Mode

I could also see from my physical network, that there was layer 2 connectivity happening, as it was in in the ARP cache of my core switch.


I did notice that if I waited for a long time, it would start working, so (on the Core Switch) I flushed the ARP cache, and pinged the EVE-NG device and got a response, then it worked fine from EVE-NG, (for a while, in a manner of speaking!) If I tried to NAT any other traffic, or do anything else, then the problem returned. I could keep flushing the ARP cache on the switch, but that’s a bit annoying?


Well, (in my case) the problem turned out to be a problem with the fact I have ‘teamed‘ physical NICs on the vSwitch, which you can see above (vmnic0, and vmnic7). AS SOON as I removed one, and only had one physical uplink it worked faultlessly?

EVE-NG on ESXi ARP Problem

Everything works now.

EVE-NG To Internet Problem

Note: I tried changing the load balancing algorithms to ‘Route based on IP hash‘, ‘Route based on source MAC hash, and even ‘Use Explicit failover order‘, none of these worked.

I did see other people in forums that were saying, ‘I only have one physical uplink‘, I’m suspecting that in their case, it’s promiscuous mode was missing, but feel free to comment below, if any one manages a better work-around / fix / explanation.

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Author: PeteLong

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  1. Dear Pete,

    please try to set the advanced setting ‘Net.ReversePathFwdCheckPromisc’ to ‘1’.
    After this the connection should be fine even with teaming.

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    • Sz, I am having the same problem as above, and set the setting to 1, and I am still having the same problem. Any other ideas? I could try the non-teamed NICs as described above, but I would rather not.

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      • This fixed the problem for me. You need to turn promiscuous mode off and back on again, then also shut/no shut the interface on the virtual device.

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        • Just to elaborate, this setting is found under the ESX -> Configure -> System -> Advanced System Settings -> Page 23

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  2. I manage to solve the problem from reading Greg’s comment, https://www.petenetlive.com/KB/Article/0001432

    // Greg -For your information, I use vlan tagging on my home lab. and I needed also ‘Accept Forged transmits” on top of “Promiscous mode” on my lab to make it work. \\

    After that it’s working for me with Cloud0 and i have 2 NICs

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  3. Many Thanks, I helped to fix the issue i was facing

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