ESXi 5.1 (build 3872664) host disconnecting from vCenter Server 5.5

[lstiles]

I have a host that up until a couple of weeks was happily attached to my vCenter Server. I've restarted the host a couple of times over, restarted management services at various points, checked disk space (scratch, /var/log etc.), compared the build with other servers running 5.1, and still not much to go by.

Some facts:

- the host and server cannot ping one and other but can ping other hosts

- networking on the broken host looks the same as it does elsewhere; nothing has been changed

- hpHelper service is playing up on the host and as yet has not been stopped or upgraded (I have a suspicion it could be a factor but can't act on it until the weekend)

- I have other hosts of the same hardware type (ProLiant DL360 G7) that are not giving me trouble

- I've *not* updated and packages on this host in several months

Any suggestions on where I go from here?

Thanks.

[VipalGujrathi]

i Suggest to check VPXD logs, it will give more clarity.

[lstiles]

Is there anything you recommend specifically? I've looked through various logs already, hence ending up here.

[sjesse]

vcenter needs to be able to talk to the host, if you can't ping the management ip of the host from vcenter, then you have a networking problem. If you have a firewall in between check the firewall logs to see if something changed which caused this stop.

[VipalGujrathi]

1.  You mentioned

the host and server cannot ping one and other but can ping other hosts

You mean problematic host is not reachable (ping ) from vCenter?  Can you ping vCenter from ESXi? Please check if 902 UDP is allowed from ESXi to vCenter

2. If host is responding to ping from vCenter, then i suggest try adding back to vCenter.

Note down time stamp and check in VPXD, it will give you some idea

3. If host is responding and port 902 is open, but still not able to add back to vCenter, then i suggest disconnect it and remove from inventory and re-add.

[lstiles]

Sorry for the extremely late reply.

I disabled the firewall on both vCenter and the host and they're still unable to communicate with one and other. I've been digging a bit and came across this KB: VMware Knowledge Base. I'm going to give this a try over the weekend to rule out it being a management agent issue, and at the same time reboot the host a couple more times for peace of mind.

Any other suggestions you have in the meantime I will gladly try out.