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DSeaman
Enthusiast
Enthusiast

ESXi to vCenter communications port directionality

I was reviewing the VMware KB article which describes all of the ports and protocols the various pieces of vSphere uses. The table for ESXi seems to indicate that the ESXi host never initiates communication with the vCenter server. vCenter server is always the entity which reaches out to touch the ESXi host, be it over 443, 902, 903, etc. One of my co-workers brought up the issue of the heartbeat between ESXi and vCenter. Does ESXi initiate the heartbeat or does vCenter poll the ESXi hosts?

We are putting together a detailed visio diagram of all communications, so we need to get directionality right. We found a detailed diagram on the web which drew out all the communications and it shows bi-directionality between ESXi and vCenter, which condradicts the official port table in the KB article.

Derek Seaman
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DSeaman
Enthusiast
Enthusiast

After more digging, with a regular ESX host with a firewall I found this:

<service id='0016'>

<id>vpxHeartbeats</id>

<rule>

<direction>outbound</direction>

<protocol>udp</protocol>

<port type='dst'>902</port>

<flags>-m state --state NEW</flags>

</rule>

</service>

Which seems to indicate the vpxheartbeat is initiated from the ESX host and sent to the vCenter server. vpxheartbeat isn't mentioned at all in the KB article.

Derek Seaman
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Troy_Clavell
Immortal
Immortal

don't know what you've seen, but here is some good information

http://communities.vmware.com/docs/DOC-2500

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DSeaman
Enthusiast
Enthusiast

Thanks Troy, that's a great diagram. I'm going to use that as a basis for my diagram based on ESXi 4.0. And that diagram does show a heartbeat initiated by the ESXi host, so I think the VMware port table is missing an entry.

Derek Seaman
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