Unable to connect ESXi Server via vSphere Client

[junian_dani]

Hi,

Currently, we have a problem when trying to connect to one of ESXi Server (either directly via vSphere Client or from vCenter Server). The error message appears with following information:

"vSphere Client could not connect to x.x.x.x"
"A communication error occured while sending data to the server. (The underlying connection was closed: An expected error occured on a send)" --> if directly connecting from vSphere Client

or

"Request Time Out" --> if connecting from vCenter Server

However, we can ping to this ESXi server sucessfully and we also verify the connection from ESXi console with "Test Management Network" option (with no problem).

As the first troubleshooting step, we already tried to "Restart Management Network" and then "Restart Management Agents". But, still no luck. FYI, restart the ESXi host is not an option for this case. There are several VMs which currently running for production.

Could someone find out the root cause and how to resolve this problem?

(Btw, The ESXi & vCenter Server version are 4.0 Update 2)

Thanks.

[weinstein5]

Are you going across any firewall to connect to the ESXi server? Because if you are blocking any of the required ports you will not be able to connect to the host either directly via the vSphere client or have the vCenter server connect - the required ports are:

Table 2‑5. Required Ports

Port	Description
80	vCenter Server requires port 80 for direct HTTP connections. Port 80 redirects requests to HTTPS por...http://server instead of https://server.
389	This port must be open on the local and all remote instances of vCenter Server. This is the LDAP por... If this instance is serving as the Microsoft Windows Active Directory, change the port number from 3...
443	The default port that the vCenter Server system uses to listen for connections from the vSphere Clie... The vCenter Server system also uses port 443 to listen for data transfer from the vSphere Web Access... If you use another port number for HTTPS, you must use <ip-address>:<port> when you log in to the vC...
636	For vCenter Linked Mode, this is the SSL port of the local instance. If another service is running o...
902	The default port that the vCenter Server system uses to send data to managed hosts. Managed hosts al...
902/903	Ports 902 and 903 must not be blocked between the vSphere Client and the hosts. These ports are used...
8080	Web Services HTTP. Used for the VMware VirtualCenter Management Webservices.
8443	Web Services HTTPS. Used for the VMware VirtualCenter Management Webservices.
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